PROSITE documentation PDOC51715
GB1/RHD3-type guanine nucleotide-binding (G) domain profile


The P-loop (see <PDOC00017>) 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 γ-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 (see <PDOC00449>), 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 [1,2,3,4,5,6].

The large GB1/RHD3-type G domain consists of a six-stranded β-sheet surrounded by eight helices (see <PDB:1DG3>). It contains the conserved sequence elements of GTP-binding proteins with modifications [2,4,6].

The profile we developed covers the entire GB1/RHD3-type G domain.

Last update:

April 2014 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

G_GB1_RHD3, PS51715; GB1/RHD3-type guanine nucleotide-binding (G) domain profile  (MATRIX)


1AuthorsLeipe D.D. Wolf Y.I. Koonin E.V. Aravind L.
TitleClassification and evolution of P-loop GTPases and related ATPases.
SourceJ. Mol. Biol. 317:41-72(2002).
PubMed ID11916378

2AuthorsPrakash B. Praefcke G.J.K. Renault L. Wittinghofer A. Herrmann C.
TitleStructure of human guanylate-binding protein 1 representing a unique class of GTP-binding proteins.
SourceNature 403:567-571(2000).
PubMed ID10676968

3AuthorsPrakash B. Renault L. Praefcke G.J.K. Herrmann C. Wittinghofer A.
TitleTriphosphate structure of guanylate-binding protein 1 and implications for nucleotide binding and GTPase mechanism.
SourceEMBO J. 19:4555-4564(2000).
PubMed ID10970849

4AuthorsGhosh A. Praefcke G.J.K. Renault L. Wittinghofer A. Herrmann C.
TitleHow guanylate-binding proteins achieve assembly-stimulated processive cleavage of GTP to GMP.
SourceNature 440:101-104(2006).
PubMed ID16511497

5AuthorsStefano G. Renna L. Moss T. McNew J.A. Brandizzi F.
TitleIn Arabidopsis, the spatial and dynamic organization of the endoplasmic reticulum and Golgi apparatus is influenced by the integrity of the C-terminal domain of RHD3, a non-essential GTPase.
SourcePlant J. 69:957-966(2012).
PubMed ID22082223

6AuthorsByrnes L.J. Sondermann H.
TitleStructural basis for the nucleotide-dependent dimerization of the large G protein atlastin-1/SPG3A.
SourceProc. Natl. Acad. Sci. U.S.A. 108:2216-2221(2011).
PubMed ID21220294

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