p97 is a hexameric AAA+ adenosine triphosphatase (ATPase) that is an attractive target for cancer drug development. We report cryo-electron microscopy (cryo-EM) structures for adenosine diphosphate (ADP)-bound, full-length, hexameric wild-type p97 in ...
p97 is a hexameric AAA+ adenosine triphosphatase (ATPase) that is an attractive target for cancer drug development. We report cryo-electron microscopy (cryo-EM) structures for adenosine diphosphate (ADP)-bound, full-length, hexameric wild-type p97 in the presence and absence of an allosteric inhibitor at resolutions of 2.3 and 2.4 angstroms, respectively. We also report cryo-EM structures (at resolutions of ~3.3, 3.2, and 3.3 angstroms, respectively) for three distinct, coexisting functional states of p97 with occupancies of zero, one, or two molecules of adenosine 5'-O-(3-thiotriphosphate) (ATPγS) per protomer. A large corkscrew-like change in molecular architecture, coupled with upward displacement of the N-terminal domain, is observed only when ATPγS is bound to both the D1 and D2 domains of the protomer. These cryo-EM structures establish the sequence of nucleotide-driven structural changes in p97 at atomic resolution. They also enable elucidation of the binding mode of an allosteric small-molecule inhibitor to p97 and illustrate how inhibitor binding at the interface between the D1 and D2 domains prevents propagation of the conformational changes necessary for p97 function.
Organizational Affiliation:
Leidos Biomedical Research Inc., Frederick, MD 21702, USA.,Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA.,Laboratory of Cell Biology, National Cancer Institute, Bethesda, MD 20892, USA.,University of Pittsburgh Chemical Diversity Center, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Division of Biology and Biological Engineering and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91107, USA.,Small Molecule Discovery Center, Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA 94143, USA.,Laboratory of Cell Biology, National Cancer Institute, Bethesda, MD 20892, USA. ss1@nih.gov.
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