title: Convergent evolution of clamp-like binding sites in diverse chaperones.
abstract: Molecular chaperones have evolved diverse tertiary and quaternary structures to stabilize non-native polypeptides and facilitate their transition to the native state. Indeed, different families of chaperones lack sequence similarity, and few are represented ubiquitously in all three domains of life. Despite their discrete evolutionary paths, recent crystal structures reveal that many chaperones use seemingly convergent strategies to bind non-native proteins. This crystallographic evidence shows, or strongly suggests, that chaperones including prefoldin, Skp, trigger factor, Hsp40 and Hsp90 have clamp-like structural features used to grip substrate proteins. We explore the notion that clamp-like structures are evolutionarily favored by both ATP-dependent and ATP-independent molecular chaperones. Presumably, clamps present a multivalent binding surface ideal for protecting unstable protein conformers until they reach the native state or are transferred to another component of the folding machinery.
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Stirling
authors.forename: Samuel F
authors.initials: SF
authors.lastname: Bakhoum
authors.forename: Andrea B
authors.initials: AB
authors.lastname: Feigl
authors.forename: Michel R
authors.initials: MR
authors.lastname: Leroux
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D019143:Evolution, Molecular; D006360:Heat-Shock Proteins / Q000737:chemistry*; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D000255:Adenosine Triphosphate