Motor Mechanism for Protein Threading through Hsp104

• Main Authors: Wendler, Petra (Author), Shorter, James (Author), Snead, David (Author), Plisson, Celia (Author), Clare, Daniel K. (Author), Saibil, Helen R. (Author), Lindquist, Susan (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Biology (Contributor), Whitehead Institute for Biomedical Research (Contributor)
• Format: Article
• Language: English
• Published: Elsevier, 2012-05-25T22:09:00Z.
• Subjects: Article
• Online Access: Get fulltext

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.
European Union Integrated Project 3D-Repertoire and 3DEM Network of Excellence
Human Frontier Science Program (Strasbourg, France)
Wellcome Trust (London, England)
National Institutes of Health (U.S.) (Director's New Innovator Award DP2OD002177)
National Institutes of Health (U.S.)