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Molecular basis of [PSI+] yeast prion nucleation

Date

2013

Authors

Ben Musa, Zobaida A., author
Ross, Eric, advisor
Crans, Debbie, committee member
Zabel, Mark, committee member
Di Pietro, Santiago, committee member

Journal Title

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Volume Title

Abstract

Many fatal diseases arise from the conversion of soluble, functional proteins to insoluble misfolded amyloid aggregates. Amyloid fibers are characterized by filamentous morphology, protease resistance and cross]beta structure. Prions (infectious amyloids) are a specific subset of amyloid fibers, differing from other classes of amyloids by their infectivity. Prions are found in both mammals and yeasts, but there are differences between these two groups. Most yeast prions are characterized by the presence of large numbers of glutamine and asparagine (Q/N) residues, and some other common characteristics have been noted, including the presence of few hydrophobic and charged residues. Although, several attempts have been made with limited success to develop valuable systems to predict prion activity, there is no accurate algorithm that has the ability to predict the prion-forming proteins among the Q/N-rich protein group. In the yeast, it has been shown that amino acid composition, not primary sequence, drives prion activity. Recently, preliminary efforts to define the role of amino acid composition in prion formation have been examined. The fundamental question of this project is how, in yeast Q/N-rich prions, the sequence requirements for nucleation versus propagation differ, and how this information can be used in order to develop a precise prion prediction system. By answering this question we will be able to more accurately identify additional prions in both yeast and other organisms. Our long-term goal in the comprehensive studies of prion formation and propagation mechanisms is to apply this information to mammalian prion diseases. Consequently, we will be able to identify targets for therapeutic intervention to avoid, slow-down, or reverse the development of related diseases. The study determined that the amino acids required for prion formation differ from those required for prion propagation. Identifying the sequence feature for both activities is the first step towards mechanistic studies to examine how these sequences perform their function.

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Subject

prion
sup35

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