Anand, Shashi and Ganaie, Arsheed Ahmad and Sharma, Charu (2019) Differential thermal stability, conformational stability and unfolding behavior of Eis proteins from Mycobacterium smegmatis and Mycobacterium tuberculosis. PloS one, 14 (3). e0213933. ISSN 1932-6203

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Official URL: https://journals.plos.org/plosone/article?id=10.13...

Abstract

Eis (Enhanced Intracellular Survival) is an important aminoglycoside N-acetyltransferase enzyme contributing to kanamycin resistance in Mtb clinical isolates. Eis proteins from M. tuberculosis (RvEis) and M. smegmatis (MsEis) have 58% identical and 69% similar amino acid sequences and acetylate aminoglycosides at multiple amines. Both the Eis proteins are hexameric and composed of two symmetric trimers. RvEis has remarkable structural stability and heat-stable aminoglycoside acetyltransferase activity. Although the structure and biochemical properties of MsEis have been studied earlier, the detailed characterization of its acetyltransferase activity and structural stability is lacking. In this study, we have performed comparative analysis of structural stability and aminoglycoside acetyltransferase activity of RvEis and MsEis proteins. Unlike RvEis, MsEis undergoes a three-state unfolding induced by heat or chemical denaturants and involves self-association of partially unfolded oligomers to form high molecular weight soluble aggregates. MsEis is highly susceptible to chemical denaturants and unfolds completely at lower concentrations of GdmCl and urea when compared to RvEis. In contrast to RvEis, the oligomeric forms of MsEis are SDS sensitive. However, SDS treatment resulted in increased helix formation in MsEis than RvEis. MsEis shows lesser thermostable activity with a decreased efficiency of kanamycin acetylation in comparison to RvEis. Furthermore, overexpression of MsEis does not provide thermal resistance to M. smegmatis unlike RvEis. Collectively, this study reveals that homologous proteins from pathogenic and nonpathogenic mycobacteria follow different modes of unfolding and demonstrate differential structural stability and activity despite highly similar sequences and oligomeric organization.

Item Type: Article
Additional Information: This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Subjects: Q Science > QR Microbiology
Depositing User: Dr. K.P.S.Sengar
Date Deposited: 19 Aug 2019 09:41
Last Modified: 19 Aug 2019 09:41
URI: http://crdd.osdd.net/open/id/eprint/2420

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