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FEBS Open Bio. 2012 Jul 27;2:173-7. doi: 10.1016/j.fob.2012.07.008. Print 2012.

Exploring potassium-dependent GTP hydrolysis in TEES family GTPases.

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  • 1Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.

Abstract

GTPases are important regulatory proteins that hydrolyze GTP to GDP. A novel GTP-hydrolysis mechanism is employed by MnmE, YqeH and FeoB, where a potassium ion plays a role analogous to the Arginine finger of the Ras-RasGAP system, to accelerate otherwise slow GTP hydrolysis rates. In these proteins, two conserved asparagines and a 'K-loop' present in switch-I, were suggested as attributes of GTPases employing a K(+)-mediated mechanism. Based on their conservation, a similar mechanism was suggested for TEES family GTPases. Recently, in Dynamin, Fzo1 and RbgA, which also conserve these attributes, a similar mechanism was shown to be operative. Here, we probe K(+)-activated GTP hydrolysis in TEES (TrmE-Era-EngA-YihA-Septin) GTPases - Era, EngB and the two contiguous G-domains, GD1 and GD2 of YphC (EngA homologue) - and also in HflX, another GTPase that also conserves the same attributes. While GD1-YphC and Era exhibit a K(+)-mediated activation of GTP hydrolysis, surprisingly GD2-YphC, EngB and HflX do not. Therefore, the attributes identified thus far, do not necessarily predict a K(+)-mechanism in GTPases and hence warrant extensive structural investigations.

KEYWORDS:

EngA, Essential Neisseria gonorrhoeae GTPase; Era, E. coli ras; GTPases; HAS-GTPases; HAS-GTPases, Hydrophobic Amino acid Substituted for catalytic glutamine-GTPases; Hydrolysis mechanism; K+ stimulated hydrolysis; K-loop; TEES, TrmE-Era-EngA-YihA-Septin

PMID:
23650596
[PubMed]
PMCID:
PMC3642159
Free PMC Article
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