GB1/RHD3-type guanine nucleotide-binding (G) domain
IPR030386
Definition
The P-loop guanosine triphosphatases (GTPases) control a multitude of biological processes, ranging from cell division, cell cycling, and signal transduction, to ribosome assembly and protein synthesis. GTPases exert their control by interchanging between an inactive GDP-bound state and an active GTP-bound state, thereby acting as molecular switches. The common denominator of GTPases is the highly conserved guanine nucleotide-binding (G) domain that is responsible for binding and hydrolysis of guanine nucleotides. The GB1/RHD3 GTPase family contains a large G domain (~230 amino acids). It is widespread in eukaryotes, but not detectable in bacteria or archaea. One conserved subfamily is typified by the Arabidopsis protein root hair defective 3 (RHD3), whose othologs are present in all crown group eukaryotes. The other subfamily is typified by the interferon gamma-induced antiviral GB1 protein that is conserved in animals. The other GTPases of this subfamily are the brain finger proteins (BFPs), in which the GTPase domain is combined with an N-terminal RING finger domain, which implicates these proteins in ubiquitin-mediated signaling. Most members of this family have a large C-terminal, α-helical extension that probably participates in protein-protein interactions. The GB1/RHD3-type G domain has a low intrinsic affinity for nucleotide and often depends on nucleotide-dependent homodimerization to facilitate GTP hydrolysis [[cite:PMID:11916378], [cite:PMID:10676968], [cite:PMID:10970849], [cite:PMID:16511497], [cite:PMID:22082223], [cite:PMID:21220294]]. The large GB1/RHD3-type G domain consists of a six-stranded β-sheet surrounded by eight helices. It contains the conserved sequence elements of GTP-binding proteins with modifications [[cite:PMID:10676968], [cite:PMID:16511497], [cite:PMID:21220294]].
11 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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