|PROSITE documentation PDOC51712|
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 . 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.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Leipe D.D. Wolf Y.I. Koonin E.V. Aravind L.|
|Title||Classification and evolution of P-loop GTPases and related ATPases.|
|Source||J. Mol. Biol. 317:41-72(2002).|
|2||Authors||Hwang J. Inouye M.|
|Title||An essential GTPase, der, containing double GTP-binding domains from Escherichia coli and Thermotoga maritima.|
|Source||J. Biol. Chem. 276:31415-31421(2001).|
|3||Authors||Muench S.P. Xu L. Sedelnikova S.E. Rice D.W.|
|Title||The essential GTPase YphC displays a major domain rearrangement associated with nucleotide binding.|
|Source||Proc. Natl. Acad. Sci. U.S.A. 103:12359-12364(2006).|
|4||Authors||Agarwal N. Pareek M. Thakur P. Pathak V.|
|Title||Functional characterization of EngA(MS), a P-loop GTPase of Mycobacterium smegmatis.|
|Source||PLoS ONE 7:E34571-E34571(2012).|
|5||Authors||Foucher A.-E. Reiser J.-B. Ebel C. Housset D. Jault J.-M.|
|Title||Potassium acts as a GTPase-activating element on each nucleotide-binding domain of the essential Bacillus subtilis EngA.|
|Source||PLoS ONE 7:E46795-E46795(2012).|