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  • 1
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    Hsp104 catalyzes formation and elimination of self-replicating Sup35 prion conformers (2004)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2004-05-25
    Description: The protein-remodeling factor Hsp104 governs inheritance of [PSI+], a yeast prion formed by self-perpetuating amyloid conformers of the translation termination factor Sup35. Perplexingly, either excess or insufficient Hsp104 eliminates [PSI+]. In vitro, at low concentrations, Hsp104 catalyzed the formation of oligomeric intermediates that proved critical for the nucleation of Sup 35 fibrillization de novo and displayed a conformation common among amyloidogenic polypeptides. At higher Hsp104 concentrations, amyloidogenic oligomerization and contingent fibrillization were abolished. Hsp104 also disassembled mature fibers in a manner that initially exposed new surfaces for conformational replication but eventually exterminated prion conformers. These Hsp104 activities differed in their reaction mechanism and can explain [PSI+] inheritance patterns.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shorter, James -- Lindquist, Susan -- GM25874/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Jun 18;304(5678):1793-7. Epub 2004 May 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15155912" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphatases/metabolism ; Adenosine Triphosphate/metabolism ; Amyloid/chemistry ; Amyloid beta-Peptides/chemistry/immunology ; Antibodies/immunology ; Biopolymers ; Catalysis ; Heat-Shock Proteins/chemistry/genetics/*metabolism ; Hydrolysis ; Mutation ; Peptide Fragments/chemistry/immunology ; Peptide Termination Factors ; Prions/*chemistry/*metabolism ; Protein Conformation ; Protein Structure, Tertiary ; Saccharomyces cerevisiae Proteins/*chemistry/genetics/*metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 2
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    Ratchet-like polypeptide translocation mechanism of the AAA+ disaggregase Hsp104 (2017)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2017-07-21
    Description: Hsp100 polypeptide translocases are conserved members of the AAA+ family (adenosine triphosphatases associated with diverse cellular activities) that maintain proteostasis by unfolding aberrant and toxic proteins for refolding or proteolytic degradation. The Hsp104 disaggregase from Saccharomyces cerevisiae solubilizes stress-induced amorphous aggregates and amyloids. The structural basis for substrate recognition and translocation is unknown. Using a model substrate (casein), we report cryo–electron microscopy structures at near-atomic resolution of Hsp104 in different translocation states. Substrate interactions are mediated by conserved, pore-loop tyrosines that contact an 80-angstrom-long unfolded polypeptide along the axial channel. Two protomers undergo a ratchet-like conformational change that advances pore loop–substrate interactions by two amino acids. These changes are coupled to activation of specific nucleotide hydrolysis sites and, when transmitted around the hexamer, reveal a processive rotary translocation mechanism and substrate-responsive flexibility during Hsp104-catalyzed disaggregation.
    Keywords: Biochemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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