Motor Mechanism for Protein Threading through Hsp104
Author(s)Wendler, Petra; Shorter, James; Snead, David; Plisson, Celia; Clare, Daniel K.; Saibil, Helen R.; Lindquist, Susan; ... Show more Show less
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The protein-remodeling machine Hsp104 dissolves amorphous aggregates as well as ordered amyloid assemblies such as yeast prions. Force generation originates from a tandem AAA+ (ATPases associated with various cellular activities) cassette, but the mechanism and allostery of this action remain to be established. Our cryoelectron microscopy maps of Hsp104 hexamers reveal substantial domain movements upon ATP binding and hydrolysis in the first nucleotide-binding domain (NBD1). Fitting atomic models of Hsp104 domains to the EM density maps plus supporting biochemical measurements show how the domain movements displace sites bearing the substrate-binding tyrosine loops. This provides the structural basis for N- to C-terminal substrate threading through the central cavity, enabling a clockwise handover of substrate in the NBD1 ring and coordinated substrate binding between NBD1 and NBD2. Asymmetric reconstructions of Hsp104 in the presence of ATPγS or ATP support sequential rather than concerted ATP hydrolysis in the NBD1 ring.
Departmentmove to dc.description.sponsorship; Massachusetts Institute of Technology. Department of Biology; Whitehead Institute for Biomedical Research
Wendler, Petra et al. “Motor Mechanism for Protein Threading Through Hsp104.” Molecular Cell 34.1 (2009): 81–92. Web. 25 May 2012. © 2009 Elsevier Inc.
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