TY - JOUR

T1 - Contributions of the prion protein sequence, strain, and environment to the species barrier

AU - Sharma, Aditi

AU - Bruce, Kathryn L.

AU - Chen, Buxin

AU - Gyoneva, Stefka

AU - Behrens, Sven H.

AU - Bommarius, Andreas S.

AU - Chernoff, Yury O.

N1 - Funding Information: Supported by the National Science Foundation - Industry/University Cooperative Research Center, Center for Pharmaceutical Development (National Science Foundation Grant 0969003). To whom correspondence may be addressed: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Engineered Biosystems Building, M/C 2000, 950 Atlantic Dr., Atlanta,GA30332-2000. Tel.: (404) 385-1334; E-mail: andreas.bommarius@chbe.gatech.edu. 3 Supported by a Graduate Assistance in the Areas of National Need fellowship from the U.S. Department of Education. 4 Present address: COI Pharmaceuticals Inc., 11099 N. Torrey Pines Rd., Ste. 290, La Jolla, CA 92037. 5 Supported by a Petite undergraduate research scholarship from the Institute for Bioengineering and Bioscience. Present address: Biogen, 225 Binney St., Cambridge, MA 02142. 6 Supported by Russian Science Foundation Grant 14-50-00069 and Russian Foundation for Basic Research Grant 15-04-06650. To whom correspondence may be addressed: School of Biology, Georgia Institute of Technology, Engineered Biosystems Building, M/C 2000, 950 Atlantic Dr., Atlanta, GA 30332-2000. Tel.: 404-894-1157; Fax: 404-894-0519; E-mail: yury. chernoff@biology.gatech.edu. Publisher Copyright: Copyright © 2016 by The American Society for Biochemistry and Molecular Biology, Inc. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.

PY - 2016/1/15

Y1 - 2016/1/15

N2 - Amyloid propagation requires high levels of sequence specificity so that only molecules with very high sequence identity can form cross-β-sheet structures of sufficient stringency for incorporation into the amyloid fibril. This sequence specificity presents a barrier to the transmission of prions between two species with divergent sequences, termed a species barrier. Here we study the relative effects of protein sequence, seed conformation, and environment on the species barrier strength and specificity for the yeast prion protein Sup35p from three closely related species of the Saccharomyces sensu stricto group; namely, Saccharomyces cerevisiae, Saccharomyces bayanus, and Saccharomyces paradoxus. Through in vivo plasmid shuffle experiments, we show that the major characteristics of the transmission barrier and conformational fidelity are determined by the protein sequence rather than by the cellular environment. In vitro data confirm that the kinetics and structural preferences of aggregation of the S. paradoxus and S. bayanus proteins are influenced by anions in accordance with their positions in the Hofmeister series, as observed previously for S. cerevisiae. However, the specificity of the species barrier is primarily affected by the sequence and the type of anion present during the formation of the initial seed, whereas anions present during the seeded aggregation process typically influence kinetics rather than the specificity of prion conversion. Therefore, our work shows that the protein sequence and the conformation variant (strain) of the prion seed are the primary determinants of cross-species prion specificity both in vivo and in vitro.

AB - Amyloid propagation requires high levels of sequence specificity so that only molecules with very high sequence identity can form cross-β-sheet structures of sufficient stringency for incorporation into the amyloid fibril. This sequence specificity presents a barrier to the transmission of prions between two species with divergent sequences, termed a species barrier. Here we study the relative effects of protein sequence, seed conformation, and environment on the species barrier strength and specificity for the yeast prion protein Sup35p from three closely related species of the Saccharomyces sensu stricto group; namely, Saccharomyces cerevisiae, Saccharomyces bayanus, and Saccharomyces paradoxus. Through in vivo plasmid shuffle experiments, we show that the major characteristics of the transmission barrier and conformational fidelity are determined by the protein sequence rather than by the cellular environment. In vitro data confirm that the kinetics and structural preferences of aggregation of the S. paradoxus and S. bayanus proteins are influenced by anions in accordance with their positions in the Hofmeister series, as observed previously for S. cerevisiae. However, the specificity of the species barrier is primarily affected by the sequence and the type of anion present during the formation of the initial seed, whereas anions present during the seeded aggregation process typically influence kinetics rather than the specificity of prion conversion. Therefore, our work shows that the protein sequence and the conformation variant (strain) of the prion seed are the primary determinants of cross-species prion specificity both in vivo and in vitro.

KW - Hofmeister series

KW - amyloid

KW - prion

KW - protein conformation

KW - protein evolution

KW - species barrier

KW - yeast

UR - http://www.scopus.com/inward/record.url?scp=84954538033&partnerID=8YFLogxK

U2 - 10.1074/jbc.M115.684100

DO - 10.1074/jbc.M115.684100

M3 - Article

C2 - 26565023

VL - 291

SP - 1277

EP - 1288

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 3

ER -