PROSITE documentation PDOC51712
EngA-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.

EngA (Essential neisserial GTPase A) proteins belong to TrmE-Era-EngA-YihA-Septin like superfamily of TRAFAC class and form a unique family of bacterial GTPases with two G domains in tandem, namely GD1 and GD2, followed by a C-terminal KH-like domain. They have been shown to interact with the bacterial ribosome and to be involved in its biogenesis [1,2,3,4,5].

The EngA-type G domains consist of ~159-170 amino acid residues and show sequence homology to the Era-type G domain. The EngA-type G domain has thus also been termed Der, because it has double Era-like G domains [2]. The EngA-type G domain is composed of 5 α helices and 6 β sheets linked by characteristic loops constituting switch I and II (see <PDB:2HJG>). Each EngA-type G domain contains conserved residues organized in five distinct motifs numbered G1-G5. In the G1/Walker A motifs of EngA (Gx(4)GKS) or P-loop, the two invariant lysine residues are known to coordinate the phosphate of nucleotide. G2 (DxxG) belongs to the loop forming switch I and interacts with a Mg(2+) ion as well as the G3/Walker B motif (DxxG). G4 has a characteristic NKxD sequence that is unique to GTPases and provides specificity to GTP. The G5 motif (SA) is less obvious.

The profile we developed covers the entire EngA-type G domain.

Last update:

March 2014 / First entry.


Technical section

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

G_ENGA, PS51712; EngA-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

2AuthorsHwang J. Inouye M.
TitleAn essential GTPase, der, containing double GTP-binding domains from Escherichia coli and Thermotoga maritima.
SourceJ. Biol. Chem. 276:31415-31421(2001).
PubMed ID11387344

3AuthorsMuench S.P. Xu L. Sedelnikova S.E. Rice D.W.
TitleThe essential GTPase YphC displays a major domain rearrangement associated with nucleotide binding.
SourceProc. Natl. Acad. Sci. U.S.A. 103:12359-12364(2006).
PubMed ID16894162

4AuthorsAgarwal N. Pareek M. Thakur P. Pathak V.
TitleFunctional characterization of EngA(MS), a P-loop GTPase of Mycobacterium smegmatis.
SourcePLoS ONE 7:E34571-E34571(2012).
PubMed ID22506030

5AuthorsFoucher A.-E. Reiser J.-B. Ebel C. Housset D. Jault J.-M.
TitlePotassium acts as a GTPase-activating element on each nucleotide-binding domain of the essential Bacillus subtilis EngA.
SourcePLoS ONE 7:E46795-E46795(2012).
PubMed ID23056455

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