title: Probing the dynamic process of encapsulation in Escherichia coli GroEL.
abstract: Kinetic analyses of GroE-assisted folding provide a dynamic sequence of molecular events that underlie chaperonin function. We used stopped-flow analysis of various fluorescent GroEL mutants to obtain details regarding the sequence of events that transpire immediately after ATP binding to GroEL and GroEL with prebound unfolded proteins. Characterization of GroEL CP86, a circularly permuted GroEL with the polypeptide ends relocated to the vicinity of the ATP binding site, showed that GroES binding and protection of unfolded protein from solution is achieved surprisingly early in the functional cycle, and in spite of greatly reduced apical domain movement. Analysis of fluorescent GroEL SR-1 and GroEL D398A variants suggested that among other factors, the presence of two GroEL rings and a specific conformational rearrangement of Helix M in GroEL contribute significantly to the rapid release of unfolded protein from the GroEL apical domain.
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Tottori, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Mizuta
authors.forename: Kasumi
authors.initials: K
authors.lastname: Ando
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Uemura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawata
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Mizobata
mesh_terms: D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D017433:Protein Structure, Secondary
chemical_list: D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; D006360:Heat-Shock Proteins