Concerted ATP-induced allosteric transitions in GroEL facilitate release of protein substrate domains in an all-or-none manner.
The double-ring chaperonin GroEL mediates protein folding, in conjunction with its helper protein GroES, by undergoing ATP-induced conformational changes that are concerted within each heptameric ring. Here we have examined whether the concerted nature of these transitions is responsible for protein substrate release in an all-or-none manner. Two chimeric substrates were designed, each with two different reporter activities that were recovered after denaturation in GroES-dependent and independent fashions, respectively. The refolding of the chimeras was monitored in the presence of GroEL variants that undergo ATP-induced intraring conformational changes that are either sequential (F44W/D155A) or concerted (F44W). Our results show that release of a protein substrate from GroEL in a domain-by-domain fashion is favored when the intraring allosteric transitions of GroEL are sequential and not concerted.
Kipnis
Yakov
Y
Departments of Structural Biology and Chemical Physics, The Weizmann Institute of Science, Rehovot 76100, Israel.
Papo
Niv
N
Haran
Gilad
G
Horovitz
Amnon
A
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000494:Allosteric Regulation; D018834:Chaperonin 60 / Q000737:chemistry* / Q000378:metabolism; D002850:Chromatography, Gel; D004926:Escherichia coli; D049452:Green Fluorescent Proteins; D008958:Models, Molecular; D009841:Oligonucleotides; D017510:Protein Folding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013884:Thiosulfate Sulfurtransferase
D018834:Chaperonin 60; D009841:Oligonucleotides; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D000255:Adenosine Triphosphate; D013884:Thiosulfate Sulfurtransferase