title: Single-molecule fluorescence polarization study of conformational change in archaeal group II chaperonin.
abstract: Group II chaperonins found in archaea and in eukaryotic cytosol mediate protein folding without a GroES-like cofactor. The function of the cofactor is substituted by the helical protrusion at the tip of the apical domain, which forms a built-in lid on the central cavity. Although many studies on the change in lid conformation coupled to the binding and hydrolysis of nucleotides have been conducted, the molecular mechanism of lid closure remains poorly understood. Here, we performed a single-molecule polarization modulation to probe the rotation of the helical protrusion of a chaperonin from a hyperthermophilic archaeum, Thermococcus sp. strain KS-1. We detected approximately 35° rotation of the helical protrusion immediately after photorelease of ATP. The result suggests that the conformational change from the open lid to the closed lid state is responsible for the approximately 35° rotation of the helical protrusion.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Iizuka
authors.forename: Taro
authors.initials: T
authors.lastname: Ueno
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Morone
authors.forename: Takashi
authors.initials: T
authors.lastname: Funatsu
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry*; D056385:Group II Chaperonins / Q000737:chemistry*; D008859:Microscopy, Polarization; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D019712:Thermococcus / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D056385:Group II Chaperonins