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1am4
From Proteopedia
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COMPLEX BETWEEN CDC42HS.GMPPNP AND P50 RHOGAP (H. SAPIENS)
Overview
Small G proteins transduce signals from plasma-membrane receptors to, control a wide range of cellular functions. These proteins are clustered, into distinct families but all act as molecular switches, active in their, GTP-bound form but inactive when GDP-bound. The Rho family of G proteins, which includes Cdc42Hs, activate effectors involved in the regulation of, cytoskeleton formation, cell proliferation and the JNK signalling pathway., G proteins generally have a low intrinsic GTPase hydrolytic activity but, there are family-specific groups of GTPase-activating proteins (GAPs) that, enhance the rate of GTP hydrolysis by up to 10(5) times. We report here, the crystal structure of Cdc42Hs, with the non-hydrolysable GTP analogue, GMPPNP, in complex with the GAP domain of p50rhoGAP at 2.7A resolution. In, the complex Cdc42Hs interacts, mainly through its switch I and II regions, with a shallow pocket on rhoGAP which is lined with conserved residues., Arg 85 of rhoGAP interacts with the P-loop of Cdc42Hs, but from, biochemical data and by analogy with the G-protein subunit G(i alpha1), we, propose that it adopts a different conformation during the catalytic cycle, which enables it to stabilize the transition state of the GTP-hydrolysis, reaction.
About this Structure
1AM4 is a Protein complex structure of sequences from Homo sapiens with MG and GNP as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of a small G protein in complex with the GTPase-activating protein rhoGAP., Rittinger K, Walker PA, Eccleston JF, Nurmahomed K, Owen D, Laue E, Gamblin SJ, Smerdon SJ, Nature. 1997 Aug 14;388(6643):693-7. PMID:9262406
Page seeded by OCA on Mon Nov 12 15:59:44 2007
