title: Kinetic analysis of conformational changes of GroEL based on the fluorescence of tyrosine 506.
abstract: The conformational changes of GroEL during the ATPase cycle in the presence of GroES were studied by measuring the fluorescence intensity time course of intrinsic tyrosine Y506, which is located near the nucleotide-binding site. A GroEL solution containing GroES was mixed with an ATP solution to initiate the reaction cycle. The tyrosine fluorescence intensity relative to that without the nucleotide reached 112% within the dead time of the apparatus (>15 s(-1)) and further increased to 123% at 0.57 s(-1) followed by a decrease to 102% at 0.32 s(-1). An initial conformational change and a second intermediate state were expected to occur in ATP-bound GroEL because similar changes were observed for the ATPase-deficient D398A mutant. The conformational change to the third intermediate state corresponded to a process during or after ATP hydrolysis because D398A had no decreasing phase. The second intermediate state before ATP hydrolysis was characterized for the first time.
authors.affiliation: Major in Integrated Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hosono
authors.forename: Taro
authors.initials: T
authors.lastname: Ueno
authors.forename: Hideki
authors.initials: H
authors.lastname: Taguchi
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Motojima
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Zako
authors.forename: Masasuke
authors.initials: M
authors.lastname: Yoshida
authors.forename: Takashi
authors.initials: T
authors.lastname: Funatsu
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D018834:Chaperonin 60 / Q000737:chemistry*; D006868:Hydrolysis; D007700:Kinetics; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D013050:Spectrometry, Fluorescence; D014443:Tyrosine / Q000032:analysis*
chemical_list: D018834:Chaperonin 60; D014443:Tyrosine; D000255:Adenosine Triphosphate