Mountain Scholar :: Browsing by Author "Kennan, Alan, committee member"

Browsing by Author "Kennan, Alan, committee member"

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Open Access
A selection of nitric oxide-releasing materials incorporating S-nitrosothiols
(Colorado State University. Libraries, 2017) Lutzke, Alec, author; Reynolds, Melissa, advisor; Henry, Charles, committee member; Kennan, Alan, committee member; Kipper, Matthew, committee member
Nitric oxide (NO) is a diatomic radical that occurs as a crucial component of mammalian biochemistry. As a signaling molecule, NO participates in the regulation of vascular tone and maintains the natural antithrombotic function of the healthy endothelium. Furthermore, NO is produced by phagocytes as part of the immune response, and exhibits both antimicrobial and wound-healing effects. In combination, these beneficial properties have led to the use of exogenous NO as a multifunctional therapeutic agent. However, the comparatively short half-life of NO under physiological conditions often renders systemic administration infeasible. This limitation is addressed by the use of NO-releasing polymeric materials, which permit the localized delivery of NO directly at the intended site of action. Such polymers have been utilized in the development of antithrombotic or antibacterial materials for biointerfacial applications, including tissue engineering and the fabrication of medical devices. NO release from polymers has most frequently been achieved through the incorporation of functional groups that are susceptible to NO-forming chemical decomposition in response to appropriate environmental stimuli. While numerous synthetic sources of NO are known, the S-nitrosothiol (RSNO) functional group occurs naturally in the form of S-nitrosocysteine residues in both proteins and small molecule species such as S-nitrosoglutathione. RSNOs are synthesized directly from thiol precursors, and their NO-forming decay has generally been established to produce the corresponding disulfide as a relatively benign organic byproduct. For these reasons, RSNOs have been conscripted as practical NO donors within a physiological environment. This dissertation describes the synthesis and characterization of RSNO-based NO-releasing polymers derived from the polysaccharides chitin and chitosan, as well as the development of amino acid ester-based NO-releasing biodegradable poly(organophosphazenes) (POPs). The broad use of chitin and chitosan in the development of materials for tissue engineering and wound treatment results in a significant overlap with the therapeutic properties of NO. NO-releasing derivatives of chitin and chitosan were prepared through partial substitution of the carbohydrate hydroxyl groups with the symmetrical dithiols 1,2-ethanedithiol, 1,3-propanedithiol, and 1,6-hexanedithiol, followed by S-nitrosation. Similarly, thiol-bearing polyphosphazenes were synthesized and used to produce NO-releasing variants. Polyphosphazenes are a unique polymer class possessing an inorganic backbone composed of alternating phosphorus and nitrogen atoms, and hydrolytically-sensitive POP derivatives with organic substituents have been prepared with distinctive physical and chemical properties. Although POPs have been evaluated as biomaterials, their potential as NO release platforms has not been previous explored. This work describes the development of NO-releasing biodegradable POPs derived from both the ethyl ester of L-cysteine and the 3-mercapto-3-methylbutyl ester of glycine. The NO release properties of all polymers were evaluated at physiological temperature and pH, and the results suggested potential suitability in future biomaterials applications.
Open Access
An investigation of the effect of surface released nitric oxide on fibrinogen adsorption
(Colorado State University. Libraries, 2014) Lantvit, Sarah Marie, author; Reynolds, Melissa, advisor; Borch, Thomas, committee member; Fisher, Ellen, committee member; Kennan, Alan, committee member; Popat, Ketul, committee member
The search for improved biomaterials is a continually ongoing effort to prevent the failure of medical devices due to blood clotting. Each group of researchers has their own set of methods to create the ideal material for biological systems. In the pursuit of materials to prevent blood clot formation, these attempts have been focused on alterations in surface properties, pre-adsorption of proteins, and release of drugs. In this work I took a high-throughput approach to the prevention of device failure by investigating a model material system. Starting with a nitric oxide (NO) releasing material, a sample preparation method was developed to ensure that surface properties could be compared to a non-NO releasing control. With this material, the effect of the NO release on fibrinogen adsorption to these surfaces could be isolated. Fibrinogen is instrumental in the formation of blood clots. Determining the effect that NO has on this protein will help determine why NO has been previously found to prevent clotting in blood-contacting systems. Once the model system was developed, further investigation into changes in the fibrinogen resulting from its interaction with the released NO could be undertaken. A full investigation was completed on control non-NO releasing, low NO flux, and high NO flux materials. A qualitative assessment of the fibrinogen adsorption shows that the high NO releasing material exhibits significantly higher fibrinogen adsorption compared to both the control and low NO flux materials. Quantitative assessment of fibrinogen adsorption was attempted through a variety of methods, which indicate that conformational changes are happening upon adsorption of fibrinogen to all materials. To this end, FTIR spectra from the adsorbed fibrinogen and native fibrinogen were compared to elucidate changes in the protein's conformation. Control and low NO flux materials had too little protein to gain insight into these changes. For the high NO flux material, the fibrinogen had a significant decrease in α-helices and an increase in random chains compared to native fibrinogen. To begin understanding the effect that these changes will have on blood clot formation, these materials were further analyzed for platelet adhesion. A comparison of the control, low NO flux, and high NO flux materials with and without fibrinogen adsorbed to the material surface shows that the fibrinogen has a distinct effect on platelet adhesion and aggregation. The high NO flux materials exhibited less aggregation and full activation of platelets when fibrinogen was adsorbed prior to incubation with platelets than if fibrinogen was not present before incubation. Overall, the effect of NO on fibrinogen adsorption can be seen through these measurements. Nitric oxide release causes an increase in fibrinogen adsorption, as well as protein reorganization. Surprisingly, we see that this adsorbed fibrinogen actually improves the viability of platelets. Further study must be done using whole blood and in vivo measurements to fully understand what effect the adsorbed fibrinogen will have on the device. Despite this we can say that the adsorption of fibrinogen onto these NO releasing materials helps to improve the biocompatibility of this biomaterial due to its bulk adsorption and conformational changes.
Open Access
Anticancer potential of nitric oxide-based therapeutics for pediatric and adult cancers
(Colorado State University. Libraries, 2021) Gordon, Jenna Leigh, author; Reynolds, Melissa, advisor; Henry, Chuck, committee member; Kennan, Alan, committee member; Brown, Mark, committee member
Based on 2015-2017 data, nearly 40% of men and women will be diagnosed with cancer at some point throughout their lives. As a worldwide pandemic, cancer presents a colossal challenge for researchers and clinicians to continually develop and implement new strategies to prevent, diagnose, and treat the many variations of this disease. Currently, treatment protocols are dominated by surgery, chemotherapy, and radiation therapy. Although valuable, these treatments are often ineffective and are limited to specific situations. Surgery is typically useful for early-stage cancer treatment while chemotherapy and radiation therapy are more common for late-stage treatment. Chemotherapy and radiation therapies are subject to drug resistance and all three produce patient side effects. Thus, a persistent need to develop drugs that are more effective, preferential (to neoplastic cells), and accessible remains. This work implements therapeutics that addresses those concerns while demonstrating efficacy within both pediatric and adult cancers. An evaluation of the anticancer potential of nitric oxide (NO) releasing S-nitrosothiol based anticancer therapeutics is presented herein. In the determination of clinical translatability of a drug, it is essential to understand the desired outcome and potential sources of error prior to execution of analyses and the corresponding methodologies and measurements. Thus, an in-depth analysis of indicators for therapeutic efficacy using tumor-derived cell lines and a detailed investigation of the protocol development and potential interferences of three common cellular viability assays is presented prior to the in vitro work detailed in this study. Specifically, this study involves the application of the NO releasing S-Nitrosothiol, S-Nitrosoglutathione (GSNO) in two variations to determine efficacy against pediatric neuroblastomas and adult breast cancers. Initially, two studies explore the application of GSNO in solution to multiple neuroblastoma cell lines of various origins to determine the potential of NO to act as an adjuvant therapeutic in the clinical management of the prevalent pediatric cancer neuroblastoma. These studies highlight the incredible impact of NO on clonogenic capacity as well as remarkable discriminatory characteristics between neoplastic and healthy cells. Further, the insight presented regarding the mechanism of action of NO on neuroblastomas expands the comprehension of NO-based anticancer therapeutics. Excitingly, when the same GSNO preparation is subsequently applied to more common adult breast cancers to determine if therapeutic efficacy is maintained, results display analogous consequences to those mentioned above. The final study in this dissertation will also explore another application of solution-phase GSNO to adult breast malignancies by combining it with a novel SMYD-3 inhibitor, termed Inhibitor-4 (by collaborators). Since Inhibitor-4 has been shown to similarly impact viability, clonogenic capacity, and apoptosis, this combination is expected to reveal a greater impact than each individual treatment. Overall, an analysis of the significance and feasibility of NO-based therapeutics, delivered via GSNO, is explored to determine their potential application in the clinical management of various cancers. Ultimately, this work expands the knowledge of the practicality, mechanism of action, and effectiveness of NO-based anticancer therapeutics in various cancers with a specific focus on its applicability in neuroblastomas, a malignancy where minimal focus has been placed on NO as a treatment option.
Open Access
Asperparaline A: biosynthetic studies and synthetic efforts
(Colorado State University. Libraries, 2008) Gray, Chandele Ramsey, author; Williams, Robert M., advisor; Kennan, Alan, committee member; Szamel, Grzegorz, committee member; Parkinson, Bruce, committee member; Brennan, Patrick, committee member
Asperparaline A, a fungal metabolite isolated from Aspergillus japonicus, is of interest due to anthelmintic activity and structural similarities to the paraherquamides and brevianamides owing to the presence of bicyclo [2.2.2] diazaoctane core proposed to be derived from a biosynthetic [4+2] cycloaddition. This communication details two aspects of research regarding asperparaline A. The first goal involves the elucidation of asperparaline A as being biosynthetically composed of dimethylallylpyrophosphate and the amino acids, tryptophan and L-isoleucine, analogous to the paraherquamides. The second goal addresses the desire to develop synthetic methodology amenable to the introduction of isotopic labels for further biosynthetic studies. The proposed retrosyntheses envision the spiro-succinimide ring of asperparaline A being introduced by the photooxidation of a suitably oxidized pyrrole ring. Synthetic approaches toward asperparaline A presented include peptide coupling of β-methylproline with a prenylated pyrolylalanine, and Horner-Wadsworth-Emmons olefination of a diketopiperazine phosphonate with various aldehydes designed to allow for late stage pyrrole synthesis.
Open Access
Characterization of poliovirus 2CATPase bound to bilayer nanodiscs and involvement of the poliovirus 3Dpol thumb α-helix in determining poly(A) tail length
(Colorado State University. Libraries, 2013) Springer, Courtney Lee, author; Peersen, Olve B., advisor; Ho, P. Shing, committee member; Luger, Karolin, committee member; Kennan, Alan, committee member
Poliovirus (PV) is a small non-enveloped picornavirus with a ≈7.5 kb long single-stranded, positive-sense RNA genome. Upon infection, the RNA is translated to generate a ≈250 kDa polyprotein that is subsequently cleaved into about a dozen fully processed proteins and several functional intermediates. PV replication occurs in large membrane associated complexes involving the "non-structural" P2 and P3 region proteins and two of these proteins, 2CATPase and 3Dpol, are the subjects of this dissertation. Part I of this work is focused on the 2C protein, an AAA+ family ATPase that plays a key role in host cell membrane rearrangements and virion assembly, but the membrane binding characteristics of 2C and its polyprotein precursors have made it difficult to elucidate their exact roles in virus replication. In this work I show that small lipid bilayers known as nanodiscs can be used to chaperone the in vitro expression of soluble poliovirus 2C and the precursor 2BC and 2BC3AB polyproteins in a membrane bound form. Biochemical analysis shows that the proteins are highly active over a wide range of salt concentrations, exhibit slight lipid headgroup dependence, and show significant stimulation by acetate. Notably, the ATPase activity of the core 2C domain is stimulated ≈60-fold as compared to the larger 2BC3AB polyprotein, with most of this stimulation occurring upon removal of 2B. This data leads to a model wherein the viral replication complex can be assembled with a minimally active form of 2C that then becomes fully activated upon proteolytic cleavage from the adjacent 2B viroporin domain. In Part II of this dissertation, I focus on the role of the viral RNA polymerase, 3Dpol, in maintaining the ≈20-150 nucleotides long 3' poly(A) tail of the viral genome. The length of the tail is important for viral replication and initiation of (-)-strand synthesis, but the means by which the RNA is polyadenylated and how poly(A) tail length is regulated is not well understood. We have identified several mutations in an α-helix of the 3Dpol thumb domain that directly impact poly(A) tail length. Here, I tested the impact of these mutations on reiterative transcription of poly(A), poly(U), and poly(C) templates as well as characterized their effect on 3Dpol initiation, stability, elongation rate, and fidelity. I found that mutations in the thumb have the greatest impact on elongation complex stability and that 3Dpol is able to reiteratively transcribe homopolymeric poly(U) and poly(A), but not poly(C) RNA templates. Interestingly, distinct poly(A) and poly(U) transcripts are generated from 10 nucleotide homopolymers that are 1, 7, or 8 nucleotides longer than the template. Based on these findings, we propose a poly(A) slippage model in which the elongation complex stalls at the end of the homopolymer stretch in the absence of additional nucleotides to promote a single nucleotide slippage. This is followed by a slow structural rearrangement in which 3Dpol slips back to the 3' end of the homopolymer sequence, where it is able to re-transcribe starting from the fifth poly(U) in the template.
Open Access
Characterization of the selective hydrolysis of branched ubiquitin chains by Uch37 and its activator Rpn13
(Colorado State University. Libraries, 2020) Hazlett, Zachary S., author; Yao, Tingting, advisor; Cohen, Robert, committee member; Peersen, Olve, committee member; Di Pietro, Santiago, committee member; Kennan, Alan, committee member
The ubiquitin (Ub) C-terminal hydrolase, Uch37, can be found associated with the 26S proteasome as well as the INO80 chromatin remodeling complex. Bound to the 26S proteasome, it assists in regulating the degradation of Ub modified proteins. The proteasomal subunit Rpn13 binds Uch37, anchors it to the proteasome 19S regulatory particle and enhances the deubiquitinating enzyme's (DUB's) catalytic activity. While the structure of the Uch37/Rpn13 complex bound to a single Ub molecule has been characterized, much still remains unknown regarding the enzyme's substrate specificity, the molecular basis for its substrate specificity, and its function in the regulation of proteasomal degradation. In this thesis we characterize the substrate specificity of Uch37 with and without its proteasomal binding partner Rpn13. By synthesizing poly-Ub chains of various linkage types and topologies and using these Ub chains in in vitro deubiquitination assays, we were able to determine that Uch37/Rpn13 selectively cleaves branched Ub chains. This provides evidence to suggest that Uch37 is the first enzyme with activity specific for branched Ub chains. Branched Ub chains have been identified endogenously and have roles connected to the regulation of nascent misfolded polypeptides, cell cycle control, and the enhancement of proteasomal degradation. The work presented here sets out to characterize the molecular mechanism of branched chain hydrolysis by Uch37 and its binding partner Rpn13, determine the kinetics of this enzymatic reaction, and establish a system for probing the function of "debranching" by Uch37 in proteasomal degradation. The conclusion of our work builds our understanding of the complex system of intracellular signaling by Ub and unveils key elements to the primary system responsible for regulating cellular protein homeostasis.
Embargo
Comparative analysis of the role of redox active molecules on bioenergetically active membranes
(Colorado State University. Libraries, 2024) Dolan, Connor Cathal, author; Crans, Debbie, advisor; Kennan, Alan, committee member; Chicco, Adam, committee member
Transition metals play crucial roles in various biological processes, with vanadium and manganese being prominent examples due to their redox activity and impact on oxidative stress, mitochondrial function, and disease progression. This manuscript focuses on the role of transition metals, particularly vanadium, in biological functioning, with an emphasis on oxidative stress and mitochondria. Chapter 1 of this thesis discusses the respective role that vanadium plays on oxidative stress and how that influences biological systems. Due to its variety of speciation states and its ability to redox cycle as well as its structural and electronic properties, vanadium can affect biological systems in a variety of ways. These include the generation of reactive oxygen species, lipid peroxidation, protein inhibition, changes in membrane fluidity and potential. DNA damage and cell death. The effects that vanadium has is highly dependent on the speciation and state that they exist in. this can impact the system that is being affected and the outcome. Species such as decavanadate have a unique and profound biological effect. Changing of the species, oxidation state and complexation can alter the biological consequences associated with vanadium. Chapter 2 of this thesis explores the differences and similarities between vanadium and manganese on cardiac mitochondrial dysfunction and oxidative stress. Using varying vanadium and manganese compounds, we investigated the effects they had on isolated cardiac mitochondria using high resolution respirometry and UV-Vis spectroscopy. We found similarities between metal salts on inhibition of respiration as well as significant differences on the metals iii effect on mitochondrial swelling. We further investigated the role of transport proteins on vanadium induced swelling and found that the mitochondrial calcium uniporter played an important role in vanadium induced mitochondrial swelling. We further investigated the differences in species and oxidation state on function. We tested the difference between VV and VIV on mitochondrial swelling and found that VIV led to significantly greater swelling. We also found that there the VO(OH)3 - monomer and dimer were present in both VIV compounds and the Mn2+ ion was present in both manganese compounds. This speciation similarity between compounds may account for some of the similar effects seen within the same metal compounds as well as the differences seen when comparing manganese and vanadium together.
Open Access
Determining driving forces for small molecule aggregation using computational and theoretical methods
(Colorado State University. Libraries, 2022) Anderson, Jakob Edward, author; Rappé, Anthony, advisor; McCullagh, Martin, advisor; Kennan, Alan, committee member; Chen, Eugene, committee member; Shipman, Patrick, committee member
Molecular aggregation is largely dictated by noncovalent interactions and is a phenomenon found in a broad list of disciplines. Computational and theoretical methods, such as molecular dynamics simulations and Quantum Mechanical calculations, are well suited techniques to study the noncovalent association of various systems as they provide atomistic resolution and experimentally comparable results for the timescales on which association occurs. The studies found in this dissertation are introduced in the first chapter and are put in the context of using computational methods to study the noncovalent association and aggregation of small molecules. Chapters two, three, and four provide a foundation for the rational design of dipeptides for a given application. A wide range of potential applications for diphenylalanine (FF) have been proposed which would benefit from the development of design principles. Chapter two discusses the complexity of the noncovalent interactions at multiple stages in the FF self-assembly process. Specifically, we suggest the initial aggregation of FF is predominantly driven by electrostatics, and after a reorientation event, nanotube growth is suggested to be driven by solvent mediated forces. The results from this chapter use an array of generalized analyses enabling quantitative comparisons to future dipeptide studies. The impact of sidechain modification for either FF residue is studied in chapter three by considering valine-phenylalanine (VF) and phenylalanine-valine (FV). While the monomeric conformations are shown to sample the same states for these two dipeptides, the probabilities for state sampling as well as the water dynamics around the peptide bond are shown to differ. Chapter four connects chapters two and three by considering both the behavior of sequence dependence and dimerization of VF, FV, isoleucine-phenylalanine, and phenylalanine-isoleucine relative to that of FF. The modification of the C-terminus of FF to a smaller hydrophobic sidechain is hypothesized to enable tighter packing from this study. Additionally, N-terminus FF modification is hypothesized to increase the solvent mediated forces during dimerization in agreement with the results from chapter three. While not a completed study, chapter four provides a foundation for the continued development of design principles for FF-derivatives. A novel approach to computing the free energy of association from Quantum Mechanical calculations is then described in chapter five. Due to the treatment of low energy frequencies as harmonic and a lack of temperature dependence, calculations of the entropy of associating molecules is inaccurate. The rigid-rotor-Gaussian-oscillator approximation proposed addresses these issues by treating low lying modes with anharmonic Gaussian potentials and wave functions as well as adding a temperature dependence to the partitioning between vibrational and translational/rotational modes. This approximation significantly reduces the error in computing the entropy of associating molecules resulting in a more accurate calculation of the total free energy. The results from these studies as well as future studies based on the work in this dissertation are then summarized in the final chapter.
Open Access
Development of an asymmetric NHC-catalyzed cascade reaction and studies towards the asymmetric aminomethylation of enals
(Colorado State University. Libraries, 2015) Ozboya, Kerem, author; Rovis, Tomislav, advisor; Henry, Charles, committee member; McNally, Andrew, committee member; Kennan, Alan, committee member; Inamine, Julia, committee member
A cascade reaction is developed to form complex cyclopentanones using an asymmetric Michael/Benzoin sequence. This reaction employs simple aliphatic aldehydes and ketoesters in conjunction with a chiral amine catalyst and a chiral NHC catalyst. Further investigation reveals a surprising interplay between these two catalysts. This relationship is manifested in a pseudo-dynamic kinetic resolution, which is responsible for the high diastereoselectivity observed. Subsequent work details the discovery of the aminomethylation of enals using NHC catalysis. This reaction utilizes an iminium source as well as cinnamaldehyde derivatives to form gamma-amino butyrate derivatives. Rendering this reaction asymmetric has proven a challenge, despite extensive effort to resolve these issues. In the course of these studies, an unexpected NHC-catalyzed Morita-Baylis-Hillman reaction was observed. Optimal conditions for this reaction were established, proving access to useful amino-enals. In an effort to design suitable catalysts for the asymmetric aminomethylation reaction, a strategy for the late-stage manipulation of NHC catalysts was developed. Key to this strategy is the `protection' of the triazolium salt by reduction to the triazoline. An aryl C-Br bond is then exploited for cross-coupling reactions, building a small library of new catalysts. The triazolium salt is then recovered by oxidation with a trityl salt.
Open Access
Donor-appended sensitizers and further exploration of cobalt polypyridyl mediators: behavior and consequences in dye-sensitized solar cells
(Colorado State University. Libraries, 2014) Ashbrook, Lance, author; Rappé, Anthony, advisor; Gelfand, Martin, committee member; Kennan, Alan, committee member; Ladanyi, Branka, committee member; Shores, Matthew, committee member
Dye-sensitized solar cells (DSCs) have been thoroughly investigated over the past two decades as viable alternatives to traditional silicon solar cells. Fueling this research is the potential for DSCs to exhibit comparable efficiencies to silicon but at a fraction of the cost due to the generally cheaper materials employed. This dissertation presents studies conducted with cobalt polypyridyl mediators as substitutes for the more commonly employed I-/I3-. In addition, several novel sensitizers are synthesized incorporating electron donors in order to separate the injected electron and subsequent hole on the dye. Chapter 1 reviews a brief history of DSC development and the relevant processes in an operational cell. The interplay of these processes is discussed. Commonly employed materials are presented as well as alternatives used in the literature and in the work throughout this dissertation. Instrumentation and methods utilized throughout this work are also discussed. The use of copper polypyridyl dyes in DSCs is discussed in Chapter 2. While there is literature precedent for these materials as sensitizers, very few studies exist due to inherent issues to the sensitizers that are not shared with the more traditional ruthenium dyes. These problems are highlighted and discussed in the context of sensitizer design. One of the primary issues is the coordination of mediator additives to the oxidized copper center, rendering it unable to participate in further photoexcitation. Studies are presented that show the incorporation of a phenothiazine-type electron donor into the sensitizer results in rapid reduction of the copper center and prevents additional coordination. Electrochemical and cell testing studies are presented in Chapter 3 that partially explain why the addition of lithium ion to the mediator solution results in better DSC current values, particularly with cobalt mediators. The electrochemistry of the Co2+/3+ couple on FTO appears to be highly dependent on cations present in solution. Li+ present in solution results in current being "shut off" at the FTO surface. Thus, Li+ addition leads to an additional charge transfer resistance at the anode which leads to a reduction in undesired electron scavenging. Although platinum films or platinized FTO are the usual materials of choice for DSC cathodes, they generally perform better when used in conjunction with I-/I3-. The cobalt complexes employed as alternative mediators tend to exhibit more reversible electrochemistry on gold, but gold cathodes have historically been difficult to fabricate reproducibly. Chapter 4 probes a sulfide modification technique that appears to improve gold cathode performance. Based on the data presented, the mediator additive t-butyl pyridine weakly adsorbs to the gold surface which disrupts the electronic coupling with an oxidized cobalt complex. Modification with sulfide ion results in a lower charge transfer resistance at the surface which translates to a better fill factor. Finally, the last chapter further explores the use of incorporating a phenothiazine electron donor into the sensitizer. In this chapter, novel ruthenium dyes are synthesized and evaluated against some commonly employed sensitizers in the literature. The relevant processes are more difficult to elucidate in these systems than in the copper systems due to the similar absorption profiles of the Ru → ligand MLCT and oxidized phenothiazine. This makes the important technique of transient absorption more problematic to employ. Therefore, the effect of the donor is evaluated based primarily off cell testing data. The de-convolution of mass transport and donor effects is attempted by comparing with Z-907, which is a commonly used sterically demanding sensitizer. Additional experiments are also suggested which would offer more insight into this competition.
Open Access
Engineering bacteriophage nanocarriers for targeted delivery of protein reagents to prostate cancer cells
(Colorado State University. Libraries, 2014) DePorter, Sandra M., author; McNaughton, Brian, advisor; Kennan, Alan, committee member; Crans, Debbie, committee member; Reynolds, Melissa, committee member; Di Pietro, Santiago, committee member
Proteinaceous reagents, including antibodies and synthetic proteins, have become some of the most effective reagents for targeted treatment and diagnosis of disease. The unique catalytic activity of some proteins and ability to bind disease-relevant receptors that can evade small molecule discovery, make these reagents well suited for use as therapeutic and bioimaging reagents. However, the large size and charge distribution of most proteins greatly inhibits their intracellular delivery to diseased cells, limiting targets to those displayed on the cell surface. In response to this challenge, we have developed a bacteriophage nanocarrier to deliver large payloads of proteinaceous cargo to the interior of prostate cancer cells. This reagent employs two distinct components: a genetically defined prostate cancer cell-selective protein transduction domain, and a biotinylation site on an orthogonal coat protein, which allows for complexation with streptavidin fusion proteins. Collectively, this approach permits targeted intracellular delivery of ~20 exogenous proteins per phage to human prostate cancer cells. This multifunctional technology offers a cell-selective solution to the challenges associated with delivering protein cargo to the interior of diseased cells and may lead to an expansion in the use of protein reagents.
Open Access
Fluid inclusion study of the Mesoproterozoic Nonesuch Formation - biogenic sources and thermal history of oil
(Colorado State University. Libraries, 2011) Colbert, Sarah Janette, author; Ridley, John, advisor; Egenhoff, Sven, committee member; Kennan, Alan, committee member
The Nonesuch Formation is part of the Mid-Continent Rift System and is unusual because it contains a relatively high amount of oil that is thought to have formed in situ during the Mesoproterozoic, approximately 1.1 Ga. In this study, primary, pseudosecondary and secondary oil inclusions in samples obtained from Nonesuch Fm outcrop and cores were analyzed using petrography and microthermometry, and one core sample was analyzed by GC-MS. Aqueous inclusions were also studied via petrography and microthermometry. The inclusions studied were hosted in sandstone grains and matrix from parts of the Nonesuch Fm and the upper part of the Copper Harbor Fm, diagenetic calcite nodules from the Marker Bed of the Nonesuch Fm and calcite veins in the Nonesuch and Upper Copper Harbor Fms that formed no later than 30 Ma after deposition. Based on these settings, it can be assumed that all inclusions studied were entrapped during the Mesoproterzoic around the time of deposition of the Nonesuch Fm. The biomarkers detected by GC-MS have a Proterozoic character and the presence of mid-chain substituted monomethyl alkanes as well as 1,2,5-TMN indicates a cyanobacterial hydrocarbon source. Algal biomarkers have also been found in the oil in previous studies. The ratios calculated from the GC-MS data suggest an early- to peak-oil window maturity for the hydrocarbons, which is consistent with data from previous studies. The homogenization temperatures obtained by microthermometry are typically used as an estimate of inclusion entrapment temperature; however, in this study, the wide range of homogenization temperatures along with an inconsistency between these and the GC-MS maturity indicators implied that the thermal history of the oil was more complex. The inclusions were likely trapped during diagenesis at temperatures between 100-130°C, which agrees with the evidence from the maturity ratios and previous work on the Nonesuch Fm, and then reheated by hydrothermal activity after entrapment. The microthermometrical evidence implies that the second period of heating raised temperatures to levels exceeding 250°C, and other studies of the Mid-Continent Rift area suggest that this secondary heating occurred either soon after diagenesis or significantly later, around 200-300 Ma.
Open Access
Functional characterization of nucleosome assembly proteins
(Colorado State University. Libraries, 2021) Krzizike, Daniel, author; Luger, Karolin, advisor; Kennan, Alan, committee member; Nyborg, Jennifer, committee member; Stargell, Laurie, committee member; Woody, Robert, committee member
The amount of DNA found within the human body will span from the earth to the sun ~50 times. With the DNA providing the genetic blueprint of all living things, it needs to be packaged in a way that allows accessibility. The first step in this packaging involves nucleosomes, large macromolecular complexes made up of histone proteins and DNA. Nucleosomes must remain dynamic as they are constantly assembled and disassembled for processes such as DNA replication, repair, and transcription. Both assembly and disassembly occur in a specific stepwise manner orchestrated by multiple proteins employed by the cell. Specifically, histone chaperones have been implicated in almost every aspect of nucleosome dynamics such as shuttling histones into the nucleus, histone storage, and both nucleosome assembly and disassembly in an ATP-independent manner. While the structures of many histone chaperones have been determined, the mechanism of how they regulate nucleosome dynamics is still largely unknown. I investigated the mechanism of the nucleosome assembly protein family (Nap family) through several biochemical approaches. The Nap family of proteins are implicated in histone homeostasis through interactions with core histones, histone variants, and linker histones. They are conserved among all eukaryotes from yeast to humans. Members of the Nap family contain a conserved core region flanked by highly disordered N- and C-terminal tails varying in length and charge between species. Using yNap1, we investigated how these tails impact the overall function in regards to histone binding, histone selectivity among core histones and histone variants, and in mediating histone-DNA interactions. We found that the tails are critical for overall function, with the charge of the tails being crucial in regulation. We also investigated Vps75, another member of the Nap family. Similar to Nap1, Vps75 binds core histones, but also stimulates the acetylation activity of Rtt109, a histone acetyltransferase. In light of a recent debate regarding the stoichiometry with which these Nap members bind their histone cargo, we characterized the Vps75-histone interaction using core histones H2A-H2B and H3-H4. Comparing Vps75 with yeast Nap1, we found that the mechanism of histone binding is not conserved among these Nap family members. Further expanding on Vps75, we investigated the interaction with Rtt109 in both the presence and absence of H3-H4. We discovered dimeric Vps75 is capable of binding either one histone tetramer or two units of Rtt109 with the ternary complex consisting of only one unit of Rtt109 and one H3-H4 tetramer. While characterizing Nap family members I became very familiar with Analytical Ultracentrifugation (AUC). AUC is a powerful in-solution technique that provides first-principle hydrodynamic information to determine size, shape, and molecular interactions, making it ideal for the characterization of proteins, DNA, and the interactions among them. As our lab traditionally used AUC to obtain van Holde-Weischet plots, an excellent graphical representation of homogeneity or heterogeneity, we incorporated new analysis techniques for improved accuracy in molecular mass and gross shape determination. Using the added-on fluorescence detection system, we obtained a level of sensitivity and selectivity that was otherwise not possible. Using the powerful method of analytical ultracentrifugation combined with fluorescent studies, we provide insight into the regulation mechanism of Nap family members along with establishing a framework to study other macromolecular complexes.
Open Access
Glyme-synthesized nanomaterials
(Colorado State University. Libraries, 2021) Armstrong, James, author; Ackerson, Christopher J., advisor; Prieto, Amy, committee member; Kennan, Alan, committee member; Basaraba, Randall, committee member
Nanomaterials include materials with at least one dimension in the nanometer range. These materials include nanoparticles, quantum dots, thin films, self-assembled materials, supramolecular materials and more. Nanoscience is an intriguing field for cutting edge research for energy, biology, medicine, optical and other applications. Coinage-metal (Au, Ag, Cu) nanomaterials are particularly of interest for the stability of nanoparticles synthesized with these metals. These metals can also be utilized to produce supramolecular assemblies, e.g. Hydrogels. In particular, this dissertation will cover four projects involving coinage metal nanomaterials. Chapter 2 discusses the ligand-exchange of a gold-thiolate nanocluster synthesized in diglyme, while chapters 3-5 investigate a unique supramolecular assembly of coinage-metal thiolates using glymes as antisolvent. Chapter 3 explores the underlying makeup of these amorphous assemblies, while chapters 4 and 5 investigate the application of this supramolecular assembly for additive manufacturing applications and antimicrobial applications, respectively. All of these products are linked through the synthesis and characterization of nanomaterials, which require the use of glymes (1,2-dme, diglyme, triglyme, etc.) as a necessary synthetic solvent or antisolvent. Nanoclusters are small, atomically precise nanoparticles with a metal core and a passivating layer of organic ligands. Coinage metal nanoclusters are studied for their stability, especially gold nanoclusters, allowing for long-term studies of properties and applications, as well as post-synthetic modifications. Precise control over ligand shell composition, particularly of mixed ligand layers is desired for control over nanocluster functionality. Supramolecular materials build bulk properties through noncovalent interactions. Self-assembled supramolecular materials utilize small molecules which assemble into larger secondary and tertiary structures. These materials are of interest for a broad range of applications like additive manufacturing and biological applications. The motivation behind this work was to explore nanomaterials which results from a glyme based synthesis. Gold nanocluster synthesis in diglyme is found to produce a stable gold-thiolate nanocluster with a single glyme ligand. The precision of a single-unique ligand could lead to further enhancements in nanocluster functionality in the future. Addition of glyme to a coinage-metal thiolate solution results in the rapid precipitation of a rigid supramolecular assembly. The resultant metallogel exhibits properties unique from similar materials without the use of glyme in synthesis. The metallogel is composed of oligomers reminiscent of nanoparticle precursors; as such, metallogel-nanoparticle composites are readily synthesized.
Open Access
Investigating the biosynthetic mechanisms of the brevianamides & penicimutamides through the total synthesis of secondary metabolites
(Colorado State University. Libraries, 2020) McCauley, Morgan Taylor, author; Bandar, Jeff, advisor; Kennan, Alan, committee member; Szamel, Grzegorz, committee member; Slayden, Richard, committee member
The class of prenylated indole alkaloids containing a bicyclo[2.2.2]diazaoctane ring system consists of secondary metabolites isolated from fungal genera that possess diverse biological activities. Recent findings have established three ways in which the bicyclic core in this class can be constructed: (1) Generation of the monoxopiperazines (malbrancheamides and related families) by an NADPH-dependent bi-functional reductase/Diels-Alderase; (2) An enantiodivergent generation of the dioxopiperazines by some cytochrome P450 creation of achiral azadienes and successive enzyme-mediated stereoselective intramolecular hetero-Diels-Alder (IMDA) reaction in the notoamide/stephacidin families; and (3): non-Diels-Alderase generation of the bicycle of the brevianamides directed by a novel cofactor-independent pinacolase, culminating in a spontaneous IMDA reaction. The goal of the current work was to employ total synthesis to assist with the full characterization of unknown metabolites and decipher biochemical mechanisms employed in fungal organisms. Through this, the first total synthesis of brevianamide X and penicimutamide E, along with the synthesis of brevianamide A, and an improved, enantioselective synthesis of brevianamide Y were completed. The details of the novel synthetic work carried out by the author can be found in Chapters 3 and 5. Further synthetic efforts to better understand and access a variety of natural products are in progress to decipher the intrinsic transformations organism found in nature harness.
Open Access
Investigating the origins of slow magnetic relaxation of S = ½ Ni(III) cyclams
(Colorado State University. Libraries, 2023) Morrison, Thomas L., author; Shores, Matthew P., advisor; Zadrozny, Joe, committee member; Kennan, Alan, committee member; Gelfand, Martin, committee member
This dissertation describes the syntheses and characterizations of several Ni(III) and Ni(II) complexes in an attempt to better understand the origin of slow magnetic relaxation, or spin reversal, in S = ½ systems by utilizing Ni(III) cyclam (1,4,8,11-tetraazacyclotetradecane) as a toy model system. The content is organized as follows: Chapter 1 provides the historical context and theory surrounding the class of materials called single molecule magnets (SMMs). Therein I describe the prototypical SMM and its primary figures of merit and characteristics, such as S and D, followed by the observation of how S = ½ systems, which have previously been shown to act as SMMs, do not fit within the context currently provided by the literature. The choice of using the Ni(III) cyclam system is then elaborated upon, along with its quirks and foibles. In Chapter 2 I describe the synthesis and magnetic characterization of three Ni(III) cyclams. The first two contain halides in the axial positions, which are 100% abundant in isotopes containing nuclear spin, and the third complex has perchlorate bound in the axial position, where oxygen is nearly nuclear spin free. Neither halide systems showed slow magnetic relaxation, but it was not clear whether it was due to the superhyperfine coupling between the nuclear and electronic spins or due to the antiferromagnetic interactions present at low temperatures. The perchlorate containing complex did show slow magnetic relaxation, consistent with the literature and our predictions. Chapter three describes the crystallographic tuning tools and corresponding magnetic properties of novel S = ½ Ni(III) cyclam complex salts: strong antiferromagnetic coupling in sulfate-bridged chain {[Ni(cyclam)(µ2-SO4)]ClO4·H2O}n and field-, temperature-, and size-dependent slow magnetic relaxation in molecular [Ni(cyclam)(HSO4)2]HSO4. I have reported two methods of manipulating the dynamic magnetic response of these coordination molecules: particle size selection and deuteration. I find that particle size dependency, which I attribute to the phonon bottleneck effect, for the magnetic dynamics in the parent protiated compound is removed in deuterated isotopologue, revealing only the faster molecular relaxation mode(s). Chapter 4 describes the synthesis and characterization of four novel Ni(III) cyclams utilizing neutral ligands in the axial positions as opposed to the anionic ones considered previously, namely [Ni(cyclam)(acetonitrile)2]X3 (X = OTf, ClO4, BF4) and [Ni(cyclam)(butyronitrile)2]OTf3. Through these complexes we probe the role of ligand charge, identity, and subtle differences in the hydrogen-bonding network on the slow magnetic relaxation of the Ni(III) ion. Chapter 5 describes the solution phase studies of [Ni(cyclam)(MeCN)2]OTf3 and [Ni(cyclam)(butyronitrile)2]OTf3 in glassy and non-glassy solvents, as well as their suitability for studying other novel species in situ that may not be able to be synthesized and measured traditionally. We find that there are significant differences in the magnetic relaxation of the Ni(III) cyclams between glassy and non-glassy solutions and discuss the possibilities these findings present. In Chapter 6 I summarize the key findings from Chapters 2-5 and propose new avenues of research for further investigating this phenomenon. Finally, in Chapter 7 I describe a different ligand involving intra-ligand π-π interactions and explore the feasibility of using such interactions for intelligently controlling and tuning the first coordination sphere geometry and electronic structure. By introducing new substituents, changes to the aromaticity, and oxidation of the ligand we are able to exhibit rational control over the crystallographic and electronic structure of the metal center.
Open Access
Measurements of current-use pesticides and oxidation products using chemical ionization mass spectrometry
(Colorado State University. Libraries, 2018) Murschell, Trey Daniel, author; Farmer, Delphine K., advisor; Borch, Thomas, committee member; Kennan, Alan, committee member; Collett, Jeffrey L., committee member
Pesticides are both naturally occurring compounds found within a variety of plant species and also synthetic chemicals that are used to protect vulnerable organisms against disease carriers, harmful pests, and intrusive or undesirable vegetation. Pesticide use has large agricultural, economic, and health benefits which include increased staple food production, protection of susceptible ecosystems and wetlands, increased productivity of the labor force via disease control, and the creation of a booming chemical industry. In the decades following the discovery of DDT's anti-insecticidal properties, organochlorine pesticides (OCPs) were generously applied across the globe. OCPs appeared to have low toxicity to mammals, chiefly humans, but had adverse effects to non-target species like fish and predatory birds. OCPs persisted in soil, air, and water, and were transported atmospherically, as far as the Arctic. The prohibition of OCPs by most nations spurred research into less harmful and persistent pesticides. These current-use pesticides (CUPs) have mostly replaced OCPs and are applied world-wide. However, recent studies revealed the transport of CUPs to remote areas, including isolated Pacific islands, high alpine mountain lakes, and, again, the Arctic. Once in the atmosphere, these pesticides undergo physical and chemical processes that affect atmospheric lifetimes and transport, and potentially change the toxicity of the parent pesticides, which can have unforeseen impacts on sensitive ecosystems and organisms. With pesticide use perpetually linked to negative health questions and concerns, atmospheric monitoring, understanding of chemical processes, and improving analytical methods is necessary. Presented in this dissertation is work towards understanding pesticides and their chemistry in the atmosphere using real time mass spectrometry. A new calibration and measurement method for four CUPs, atrazine, metolachlor, permethrin, and trifluralin is shown in Chapter 2. Iodide chemical ionization mass spectrometry (CIMS) offers a real-time, sensitive measurement technique for herbicides, as well as other low volatility species. Presented in Chapter 3, ambient pesticide spray volatilization and post-application volatilization of two chlorophenoxy acid herbicides, 2,4-D and MCPA, were measured using acetate CIMS. Concentrations of 2,4-D were highest during the application period, while MCPA concentrations increased with increasing ambient temperature. Henry's Law constants and vapor pressure were found to be predictors for spray volatilization and post-application volatilization, respectively. OH radical chemistry of three aromatic herbicides are presented in Chapter 4, along with proposed oxidation mechanisms and products. Experiments were performed in an Oxidative Flow Reactor (OFR) coupled to a switching reagent ion CIMS, for a non-targeted approach for pesticide oxidation product detection. Pesticide oxidation followed typical OH oxidation mechanisms (OH abstraction with subsequent peroxide formation, OH addition to aromatic systems). MCPA and Mecoprop-p reaction rate constants with OH radical were estimated and used to calculate their atmospheric lifetimes (3 and 5 days, respectively). Newly identified products from MCPA and triclopyr oxidation are potentially harmful to the environment and to humans. Lastly, Chapter 5 covers oxidation of two nitrogen containing herbicides, trifluralin and acetochlor and mechanisms with proposed products are shown. Trifluralin photolyzed to produce NOx, and both herbicides produced isocyanic acid (HNCO) upon OH oxidation, an atmospheric toxin.
Open Access
Methods for detecting and developing protein-protein or protein-RNA interactions
(Colorado State University. Libraries, 2014) Blakeley, Brett D., author; McNaughton, Brian, advisor; Kennan, Alan, committee member; Fisk, Nick, committee member; Reynolds, Melissa, committee member; Peersen, Olve, committee member
Potent and selective recognition of disease-relevant macromolecules - such as proteins and RNA - is the molecular basis of most pharmaceuticals . Historically, small (< 500 Da) molecules have filled this role. However, the overwhelming majority (~85%) of the proteome - and emerging therapeutic targets such as RNA - present a serious challenge to small molecule-dependent recognition. An alternative approach to potent and selective recognition and regulation of disease-relevant proteins and RNA is to use synthetic proteins. In contrast to small molecules, the size, relatively high folding energies (>10 kcal/mol) and functional group diversity (by virtue of proteinaceous amino acids) allow proteins to recognize - and potentially control - macromolecular receptors that evade small molecules. Presented here are two approaches to advancing the discovery of new proteins that recognize either disease-relevant protein or RNA targets. The first part of this thesis describes split superpositive GFP reassembly as a method to identify novel protein-protein interacting pairs in living cells (E. coli). The second part of this thesis describes basic studies to evaluate the suitability of a naturally occurring RNA Recognition Motif (RRM) as a scaffold for targeting disease-relevant RNA hairpins, and the development of new RRMs that target TAR RNA, a hairpin critical to HIV proliferation.
Open Access
Modeling conformational heterogeneity in biomolecules
(Colorado State University. Libraries, 2023) Klem, Heidi, author; Paton, Robert, advisor; McCullagh, Martin, advisor; Levinger, Nancy, committee member; Kennan, Alan, committee member; Geiss, Brian, committee member
Regulation of biocatalytic cascades is essential for biological processes but has yet to be exploited in real-world applications. Allostery is a prime example, where binding of an effector molecule alters function in a remote location of the same biomolecule. V-type allostery is especially fascinating, as the reaction rate can be either increased or decreased in response to effector binding. Determining how conformational changes affect the reaction rate is challenging due to the disparity of timescales between the underlying molecular processes. Experimental methods, such as X-ray crystallography, can help to capture large-scale conformational change. However, the resulting structures are not guaranteed to correspond to the biophysical state relevant to the research questions being addressed. Structural changes that occur during the chemical reaction are particularly elusive to this approach. To understand the connection between conformational change and catalytic consequence, a description of the reaction mechanism and relevant configurations is needed. Quantum mechanical (QM) methods can be used to propose enzyme reaction mechanisms by modeling femtosecond motions of forming and breaking bonds. Large-scale conformational changes take place over much longer timescales that cannot be simulated at the QM level, therefore requiring classical simulation techniques. This dissertation focuses on the challenges posed by conformational change in the field of computational biocatalysis. The first chapter examines the prevalence of conformational change in enzymes, its relationship to catalysis, and the difficulties it presents. The second chapter looks at the influence of active site structural features on reaction rates in the allosteric enzyme IGPS using QM approaches and energy decomposition schemes. The third chapter covers the development of methods that use molecular dynamics (MD) simulations to analyze relevant structural states from simulation data and identify long-range communication pathways in biomolecules. The fourth chapter presents a Python code, enzyASM, that automates the generation of QM-based truncated active site models and discusses ongoing developments that will aid reproducibility and standardization in this field of research. The fifth and final chapter summarizes the implications of this Thesis work in computational biocatalysis and envisions how remaining challenges can be addressed to maximize potential to solve real-world problems.
Open Access
Organic cation dynamics and property relationships in layered perovskite derivatives
(Colorado State University. Libraries, 2022) Koegel, Alexandra A., author; Neilson, James R., advisor; Ackerson, Christopher, committee member; Kennan, Alan, committee member; Sites, James, committee member
Layered hybrid halide perovskites are materials with applications in solid-state lighting due to their intrinsic white light emission. Layered hybrid perovskite derivates typically have the composition, (A')2 (A)n − 1BnX3n + 1, where A' = R−NH + 3 containing organic cation, A = methylammonium (CH3NH + 3, MA), B = Sn, Pb, X = Cl, Br, I, and n = number of inorganic octahedral layers. They are called "hybrid" materials because of the inclusion of both organic and inorganic moeities in the material. Studies on the three-dimensional perovskite family have shown correlations between restricted rotational motion of the organic cation and structural phase transitions, and electronic properties. However, several questions remain about the coupling between structure, optoelectronic properties, and organic cation dynamics in layered perovskites. Here, I show that the restriction of the organic cation dynamics influences the static inorganic structure. The relevant excited states that produce the observed white light emission are also impacted by the cation dynamics. Chapter One is an overview of layered perovskites and how their structural diversity influences myriad properties. The excited state dynamics proposed in the literature are examined with respect to broad emission. Chapter Two goes in depth and describes the interplay between organic cation dynamics and broadband emission. Quasi-elastic neutron scattering elucidates the dynamic radii of the organic cation ammonium head groups and their role in tilting the inorganic octahedral structure. The smaller crystallographic ii volumes resulting from restricted cation dynamics induces further out-of-plane octahedral tilting. This tilting gives rise to the observed white light emission by the formation of self-trapped excitons. The ammonium headgroup rotations happen on a time-scale that is faster than the recombination of the self-trapped excitons, providing multiple environments for the excited state to sample, leading to inhomogeneous broadening of the white light. In perovskite derivatives, chemical substitution provides an opportunity to change the physical structure. Chapter Three demonstrates how changing the number of inorganic layers influences the cation dynamics. The methylammonium residence times, determined from quasi-elastic neutron scattering, are shorter in the layered perovskite with more inorganic layers. The dielectric screening provided by the increased number of methylammonium cations in the material with thicker inorganic enables the faster molecular motions to occupy larger crystallographic volumes. The inorganic layer hosts the relevant frontier electronic states necessary for broad emission. The population of these frontier states is influenced by a number of factors, namely the out-of-plane tilt angle. Chemical substitution of the inorganic layer affects the out-of-plane tilting; therefore, it is necessary to control the tilt angle as a variable in order to determine a more direct correlation between cation dynamics and white light. Chapter Four discusses the effect of isotopic substitution of the organic cation as a way to understand the influence of dynamics independent of tilt angle. Calculations using a harmonic oscillator approximation show the deuteration of the ammonium headgroup is iii closely coupled to the inorganic lattice, does not have much effect on the residence times of hydrogen motion. Halide substitution in the three-dimensional perovskites leads to reduced organic cation rotation residence times and further correlates to changes in electronic properties. Neutron spectroscopy presented in Chapter Five demonstrates how substitution of the halide site influences the cation dynamics and broadband emission in layered perovskites. Materials with broad emission have a lesser extent of hydrogen rotational motion, which follows previous trends in the literature. Chapter Six further demonstrates the effect of chemical substitution on broad emission and cation dynamics. The formation of solid solutions in the three-dimensional materials influence cation dynamics and phase transitions. White light emission at room temperature is achievable with solid solutions of layered perovskite derivatives. The extent of hydrogen motion determined from neutron scattering does not follow what is previously discussed in Chapter Two. Cation dynamics modify the static inorganic structure and optoelectronic properties in complex, excited state-mediated pathways. The identity of the organic cation dictates the overall perovskite structure and influences the tilting of the octahedra. The cation dynamics influence the broad emission in layered perovskite derivatives. Characterization of these coupled behaviors enable design principles for solid-state lighting applications.