2o1t
Structure of Middle plus C-terminal domains (M+C) of GRP94
OverviewOverview
GRP94, an essential endoplasmic reticulum chaperone, is required for the conformational maturation of proteins destined for cell-surface display or export. The extent to which GRP94 and its cytosolic paralog, Hsp90, share a common mechanism remains controversial. GRP94 has not been shown conclusively to hydrolyze ATP or bind cochaperones, and both activities, by contrast, result in conformational changes and N-terminal dimerization in Hsp90 that are critical for its function. Here, we report the 2.4 A crystal structure of mammalian GRP94 in complex with AMPPNP and ADP. The chaperone is conformationally insensitive to the identity of the bound nucleotide, adopting a "twisted V" conformation that precludes N-terminal domain dimerization. We also present conclusive evidence that GRP94 possesses ATPase activity. Our observations provide a structural explanation for GRP94's observed rate of ATP hydrolysis and suggest a model for the role of ATP binding and hydrolysis in the GRP94 chaperone cycle.
About this StructureAbout this Structure
2O1T is a Single protein structure of sequence from Canis lupus familiaris. Full crystallographic information is available from OCA.
ReferenceReference
Structures of GRP94-nucleotide complexes reveal mechanistic differences between the hsp90 chaperones., Dollins DE, Warren JJ, Immormino RM, Gewirth DT, Mol Cell. 2007 Oct 12;28(1):41-56. PMID:17936703 Page seeded by OCA on Sun May 4 10:12:18 2008