1jon
From Proteopedia
GROEL (HSP60 CLASS) FRAGMENT COMPRISING RESIDUES 191-345
Overview
The chaperonin GroEL is a large complex composed of 14 identical 57-kDa subunits that requires ATP and GroES for some of its activities. We find that a monomeric polypeptide corresponding to residues 191 to 345 has the activity of the tetradecamer both in facilitating the refolding of rhodanese and cyclophilin A in the absence of ATP and in catalyzing the unfolding of native barnase. Its crystal structure, solved at 2.5 A resolution, shows a well-ordered domain with the same fold as in intact GroEL. We have thus isolated the active site of the complex allosteric molecular chaperone, which functions as a "minichaperone." This has mechanistic implications: the presence of a central cavity in the GroEL complex is not essential for those representative activities in vitro, and neither are the allosteric properties. The function of the allosteric behavior on the binding of GroES and ATP must be to regulate the affinity of the protein for its various substrates in vivo, where the cavity may also be required for special functions.
About this Structure
1JON is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Chaperone activity and structure of monomeric polypeptide binding domains of GroEL., Zahn R, Buckle AM, Perrett S, Johnson CM, Corrales FJ, Golbik R, Fersht AR, Proc Natl Acad Sci U S A. 1996 Dec 24;93(26):15024-9. PMID:8986757 Page seeded by OCA on Fri May 2 21:31:08 2008
