Analysis of the fusA2 locus encoding EFG2 in Mycobacterium smegmatis

Seshadri, Anuradha and Samhita, Laasya and Gaur, Rahul and Malshetty, Vidyasagar and Varshney, Umesh (2009) Analysis of the fusA2 locus encoding EFG2 in Mycobacterium smegmatis. In: Tuberculosis, 89 (6). pp. 453-464.

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Abstract

The translation elongation factor G (EFG) is encoded by the fusA gene.Several bacteria possess a second fusA-like locus,fusA2 which encodes EFG2. A comparison of EFG and EFG2 from various bacteria reveals that EFG2 preserves domain organization and maintains significant sequence homology with EFG, suggesting that EFG2 may function as an elongation factor. However, with the single exception of a recent study on Thermus thermophilus EFG2, this class of EFG-like factors has not been investigated. Here, we have characterized EFG2 (MSMEG_6535) from Mycobacterium smegmatis. Expression of EFG2 was detected in stationary phase cultures of M.smegmatis (Msm). Our in vitro studies show that while MsmEFG2 binds guanine nucleotides, it lacks the ribosome-dependent GTPase activity characteristic of EFGs. Furthermore,unlike MsmEFG (MSMEG_1400), MsmEFG2 failed to rescue an E. coli strain harboring a temperature-sensitive allele of EFG, for its growth at thenon-permissive temperature. Subsequent experiments showed that the fusA2 gene could be disrupted in M. smegmatis mc(2)155 with Kan(R)marker. The M. smegmatis fusA2::kan strain was viable and showed growth kinetics similar to that of the parent strain (wild-type for fusA2).However, in the growth competition assays, the disruption of fusA2 was found to confer a fitness disadvantage to M. smegmatis, raising the possibility that EFG2 is of some physiological relevance to mycobacteria.

Item Type:	Journal Article
Publication:	Tuberculosis
Publisher:	Elsevier Science
Additional Information:	copyright of this article belongs to Elsevier Science.
Keywords:	EFG2;GTPase;Mycobacterium smegmatis;Competitive fitness.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	12 Jan 2010 09:10
Last Modified:	19 Sep 2010 05:53
URI:	http://eprints.iisc.ac.in/id/eprint/25138

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