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Title: Structural determinants for protein unfolding and translocation by the Hsp104 protein disaggregase

Here, the ring-forming Hsp104 ATPase cooperates with Hsp70 and Hsp40 molecular chaperones to rescue stress-damaged proteins from both amorphous and amyloid-forming aggregates. The ability to do so relies upon pore loops present in the first ATP-binding domain (AAA-1; loop-1 and loop-2) and in the second ATP-binding domain (AAA-2; loop-3) of Hsp104, which face the protein translocating channel and couple ATP-driven changes in pore loop conformation to substrate translocation. A hallmark of loop-1 and loop-3 is an invariable and mutational sensitive aromatic amino acid (Tyr 257 and Tyr 662) involved in substrate binding. However, the role of conserved aliphatic residues (Lys 256, Lys 258, and Val 663) flanking the pore loop tyrosines, and the function of loop-2 in protein disaggregation has not been investigated. Here we present the crystal structure of an N-terminal fragment of Saccharomyces cerevisiae Hsp104 exhibiting molecular interactions involving both AAA-1 pore loops, which resemble contacts with bound substrate. Corroborated by biochemical experiments and functional studies in yeast, we show that aliphatic residues flanking Tyr 257 and Tyr 662 are equally important for substrate interaction, and abolish Hsp104 function when mutated to glycine. Unexpectedly, we find that loop-2 is sensitive to aspartate substitutions that impair Hsp104 function andmore » abolish protein disaggregation when loop-2 is replaced by four aspartate residues. Our observations suggest that Hsp104 pore loops have non-overlapping functions in protein disaggregation and together coordinate substrate binding, unfolding, and translocation through the Hsp104 hexamer.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Baylor College of Medicine, Houston, TX (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Bioscience Reports
Additional Journal Information:
Journal Volume: 37; Journal Issue: 6; Journal ID: ISSN 0144-8463
Publisher:
Portland Press - Biochemical Society
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Institutes of Health (NIH); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES
OSTI Identifier:
1461438

Lee, Jungsoon, Sung, Nuri, Yeo, Lythou, Chang, Changsoo, Lee, Sukyeong, and Tsai, Francis T. F.. Structural determinants for protein unfolding and translocation by the Hsp104 protein disaggregase. United States: N. p., Web. doi:10.1042/BSR20171399.
Lee, Jungsoon, Sung, Nuri, Yeo, Lythou, Chang, Changsoo, Lee, Sukyeong, & Tsai, Francis T. F.. Structural determinants for protein unfolding and translocation by the Hsp104 protein disaggregase. United States. doi:10.1042/BSR20171399.
Lee, Jungsoon, Sung, Nuri, Yeo, Lythou, Chang, Changsoo, Lee, Sukyeong, and Tsai, Francis T. F.. 2017. "Structural determinants for protein unfolding and translocation by the Hsp104 protein disaggregase". United States. doi:10.1042/BSR20171399. https://www.osti.gov/servlets/purl/1461438.
@article{osti_1461438,
title = {Structural determinants for protein unfolding and translocation by the Hsp104 protein disaggregase},
author = {Lee, Jungsoon and Sung, Nuri and Yeo, Lythou and Chang, Changsoo and Lee, Sukyeong and Tsai, Francis T. F.},
abstractNote = {Here, the ring-forming Hsp104 ATPase cooperates with Hsp70 and Hsp40 molecular chaperones to rescue stress-damaged proteins from both amorphous and amyloid-forming aggregates. The ability to do so relies upon pore loops present in the first ATP-binding domain (AAA-1; loop-1 and loop-2) and in the second ATP-binding domain (AAA-2; loop-3) of Hsp104, which face the protein translocating channel and couple ATP-driven changes in pore loop conformation to substrate translocation. A hallmark of loop-1 and loop-3 is an invariable and mutational sensitive aromatic amino acid (Tyr257 and Tyr662) involved in substrate binding. However, the role of conserved aliphatic residues (Lys256, Lys258, and Val663) flanking the pore loop tyrosines, and the function of loop-2 in protein disaggregation has not been investigated. Here we present the crystal structure of an N-terminal fragment of Saccharomyces cerevisiae Hsp104 exhibiting molecular interactions involving both AAA-1 pore loops, which resemble contacts with bound substrate. Corroborated by biochemical experiments and functional studies in yeast, we show that aliphatic residues flanking Tyr257 and Tyr662 are equally important for substrate interaction, and abolish Hsp104 function when mutated to glycine. Unexpectedly, we find that loop-2 is sensitive to aspartate substitutions that impair Hsp104 function and abolish protein disaggregation when loop-2 is replaced by four aspartate residues. Our observations suggest that Hsp104 pore loops have non-overlapping functions in protein disaggregation and together coordinate substrate binding, unfolding, and translocation through the Hsp104 hexamer.},
doi = {10.1042/BSR20171399},
journal = {Bioscience Reports},
number = 6,
volume = 37,
place = {United States},
year = {2017},
month = {12}
}