1f5n
From Proteopedia
HUMAN GUANYLATE BINDING PROTEIN-1 IN COMPLEX WITH THE GTP ANALOGUE, GMPPNP.
Overview
The interferon-gamma-induced guanylate-binding protein 1 (GBP1) belongs to a special class of large GTP- binding proteins of 60-100 kDa with unique characteristics. Here we present the structure of human GBP1 in complex with the non-hydrolysable GTP analogue GppNHp. Basic features of guanine nucleotide binding, such as the P-loop orientation and the Mg(2+) co-ordination, are analogous to those of Ras-related and heterotrimeric GTP-binding proteins. However, the glycosidic bond and thus the orientation of the guanine base and its interaction with the protein are very different. Furthermore, two unique regions around the base and the phosphate-binding areas, the guanine and the phosphate caps, respectively, give the nucleotide-binding site a unique appearance not found in the canonical GTP-binding proteins. The phosphate cap, which constitutes the region analogous to switch I, completely shields the phosphate-binding site from solvent such that a potential GTPase-activating protein cannot approach. This has consequences for the GTPase mechanism of hGBP1 and possibly of other large GTP-binding proteins.
About this Structure
1F5N is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Triphosphate structure of guanylate-binding protein 1 and implications for nucleotide binding and GTPase mechanism., Prakash B, Renault L, Praefcke GJ, Herrmann C, Wittinghofer A, EMBO J. 2000 Sep 1;19(17):4555-64. PMID:10970849 Page seeded by OCA on Fri May 2 15:55:49 2008
