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Purification of Hsp104, a Protein Disaggregase
Published on: September 30, 2011
Motor mechanism for protein threading through Hsp104
Petra Wendler1, James Shorter, David Snead
1Department of Crystallography, Birkbeck College, London, UK.
Molecular Cell
|April 14, 2009
Summary
The Hsp104 protein remodeler uses its AAA+ domains to dissolve protein aggregates. ATP binding and hydrolysis drive domain movements, enabling substrate threading and sequential ATP hydrolysis for protein remodeling.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biology
Background:
- Hsp104 is a protein-remodeling machine that dissolves protein aggregates, including yeast prions.
- Force generation by Hsp104 involves tandem AAA+ cassettes, but the precise mechanism remains unclear.
Purpose of the Study:
- To elucidate the mechanism of force generation and substrate processing by Hsp104.
- To understand the allosteric regulation and ATP hydrolysis cycle within Hsp104.
Main Methods:
- Cryoelectron microscopy (cryo-EM) of Hsp104 hexamers.
- Atomic model fitting to EM density maps.
- Biochemical assays to support structural findings.
Main Results:
- Cryo-EM maps revealed significant domain movements in the first nucleotide-binding domain (NBD1) upon ATP binding and hydrolysis.
- These movements reposition substrate-binding tyrosine loops, facilitating N- to C-terminal substrate threading.
- Asymmetric reconstructions suggest sequential ATP hydrolysis in the NBD1 ring.
Conclusions:
- The study provides a structural basis for Hsp104's substrate threading mechanism.
- Domain movements and sequential ATP hydrolysis in NBD1 are key to Hsp104's protein remodeling function.
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