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 ATPgammaS or ATP support sequential rather than concerted ATP hydrolysis in the NBD1 ring.
Pubmed ID: 19362537 RIS Download
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A user-sponsored molecular visualization software system on an open-source foundation. The software has the capabilities to view, render, animate, export, present and develop three dimensional molecular structures.
View all literature mentionsPortal for deposition and retrieval of cryo electron microscopy (3DEM) density maps, atomic models, and associated metadata. Global resource for 3 Dimensional Electron Microscopy structure data archiving and retrieval, news, events, software tools, data standards, validation methods.
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