1dpf
From Proteopedia
CRYSTAL STRUCTURE OF A MG-FREE FORM OF RHOA COMPLEXED WITH GDP
Overview
Mg(2+) ions are essential for guanosine triphosphatase (GTPase) activity and play key roles in guanine nucleotide binding and preserving the structural integrity of GTP-binding proteins. We determined the crystal structure of a small GTPase RHOA complexed with GDP in the absence of Mg(2+) at 2.0-A resolution. Elimination of a Mg(2+) ion induces significant conformational changes in the switch I region that opens up the nucleotide-binding site. Similar structural changes have been observed in the switch regions of Ha-Ras bound to its guanine nucleotide exchange factor, Sos. This RHOA-GDP structure reveals an important regulatory role for Mg(2+) and suggests that guanine nucleotide exchange factor may utilize this feature of switch I to produce an open conformation in GDP/GTP exchange.
About this Structure
1DPF is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
An open conformation of switch I revealed by the crystal structure of a Mg2+-free form of RHOA complexed with GDP. Implications for the GDP/GTP exchange mechanism., Shimizu T, Ihara K, Maesaki R, Kuroda S, Kaibuchi K, Hakoshima T, J Biol Chem. 2000 Jun 16;275(24):18311-7. PMID:10748207 Page seeded by OCA on Fri May 2 14:07:00 2008
