title: ATP dependent rotational motion of group II chaperonin observed by X-ray single molecule tracking.
abstract: Group II chaperonins play important roles in protein homeostasis in the eukaryotic cytosol and in Archaea. These proteins assist in the folding of nascent polypeptides and also refold unfolded proteins in an ATP-dependent manner. Chaperonin-mediated protein folding is dependent on the closure and opening of a built-in lid, which is controlled by the ATP hydrolysis cycle. Recent structural studies suggest that the ring structure of the chaperonin twists to seal off the central cavity. In this study, we demonstrate ATP-dependent dynamics of a group II chaperonin at the single-molecule level with highly accurate rotational axes views by diffracted X-ray tracking (DXT). A UV light-triggered DXT study with caged-ATP and stopped-flow fluorometry revealed that the lid partially closed within 1 s of ATP binding, the closed ring subsequently twisted counterclockwise within 2-6 s, as viewed from the top to bottom of the chaperonin, and the twisted ring reverted to the original open-state with a clockwise motion. Our analyses clearly demonstrate that the biphasic lid-closure process occurs with unsynchronized closure and a synchronized counterclockwise twisting motion.
authors.affiliation: CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, Kashiwa city, Chiba, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sekiguchi
authors.forename: Ayumi
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Kazuki
authors.initials: K
authors.lastname: Moriya
authors.forename: Koki
authors.initials: K
authors.lastname: Makabe
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ichiyanagi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Nozawa
authors.forename: Tokushi
authors.initials: T
authors.lastname: Sato
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Adachi
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Kuwajima
authors.forename: Masafumi
authors.initials: M
authors.lastname: Yohda
authors.forename: Yuji C
authors.initials: YC
authors.lastname: Sasaki
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism; D056385:Group II Chaperonins / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D008958:Models, Molecular; D009038:Motion; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D014965:X-Rays
chemical_list: D019843:Archaeal Proteins; D000255:Adenosine Triphosphate; D056385:Group II Chaperonins