Chaperonin GroEL meets the substrate protein as a "load" of the rings.
Chaperonin GroEL is an essential molecular chaperone that assists protein folding in the cell. With the aid of cochaperonin GroES and ATP, double ring-shaped GroEL encapsulates non-native substrate proteins inside the cavity of the GroEL-ES complex. Although extensive studies have revealed the outline of GroEL mechanism over the past decade, central questions remain: What are the in vivo substrate proteins? How does GroEL encapsulate the substrates inside the cavity in spite of an apparent entropic difficulty? Is the folding inside the GroEL-ES cavity the same as bulk spontaneous folding? In this review I summarize the recent progress on in vivo and in vitro aspects of GroEL. In particular, emerging evidence shows that the substrate protein itself influences the chaperonin GroEL structure and reaction cycle. Finally I propose the mechanistic similarity between GroEL and kinesin, a molecular motor that moves along a microtubule in an ATP-dependent manner.
Taguchi
Hideki
H
Graduate School of Frontier Sciences, University of Tokyo. taguchi@k.u-tokyo.ac.jp
D000255:Adenosine Triphosphate / Q000378:metabolism; D018835:Chaperonin 10 / Q000502:physiology; D018834:Chaperonin 60 / Q000502:physiology*; D004529:Egg White; D004926:Escherichia coli / Q000502:physiology; D006358:Hot Temperature; D016547:Kinesins / Q000502:physiology; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000502:physiology; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D046188:Protein Modification, Translational; D011499:Protein Processing, Post-Translational; D016963:Thermus thermophilus / Q000502:physiology
D018835:Chaperonin 10; D018834:Chaperonin 60; D020409:Molecular Motor Proteins; D000255:Adenosine Triphosphate; D016547:Kinesins