OBG-type guanine nucleotide-binding (G) domain
IPR031167
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. Within the translation factor-related (TRAFAC) class of P-loop GTPases, the OBG family comprises a group of high-molecular mass GTPases conserved from bacteria to eukaryotes. The OBG family consists of PMID:11916378: Obg from bacteria and eukaryotes [[cite:PMID:12429099], [cite:PMID:15019792]]. DRG from eukaryotes and archaea. DRG proteins may regulate fundamental cellular processes through RNA binding PMID:14644502. Nog1 from eukaryotes and archaea. It is involved in the assembly of the large ribosomal subunit. Yyaf/YchF from bacteria and eukaryotes. It consists of a central G domain, flanked by a coiled-coil domain and a TGS (ThrRS, GTPase, SpoT) domain. Members of this subfamily bind and hydrolyse ATP more efficiently than GTP [[cite:PMID:12837776], [cite:PMID:17430889]]. Ygr210 from archaea and fungi. The OBG-type G domain has a mononucleotide binding fold typical for the P-loop NTPases. A six-stranded mostly parallel β-sheet is flanked by α-helices on both sides. The OBG-type G domain contains five characteristic sequence motifs, termed G1-G5, involved in nucleotide binding and hydrolysis. The G1/Walker A motif (GXXXXGK(S/T)), also referred to as P-loop, helps to position the triphosphate moiety of the bound nucleotide. The G2 (X(T/S)X) and G3/Walker B (hhhDXXG) motifs are involved in the coordination of a Mg(2)+ ion that is required for nucleotide binding and hydrolysis. Specificity in nucleotide binding is conferred by the G4 motif, which has a (N/T)KXD signature in guanine nucleotide binding P-loop NTPases. The G5 motif ((T/G)(C/S)A) supports guanine base recognition [[cite:PMID:12429099], [cite:PMID:15019792], [cite:PMID:12837776], [cite:PMID:17430889]].
6 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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