Biochemical evidence for relaxed substrate specificity of Nα-acetyltransferase (Rv3420c/rimI) of Mycobacterium tuberculosis.

Pathak, Deepika and Bhat, Aadil Hussain and Sapehia, Vandana and Rai, Jagdish and Rao, Alka (2016) Biochemical evidence for relaxed substrate specificity of Nα-acetyltransferase (Rv3420c/rimI) of Mycobacterium tuberculosis. Scientific reports, 6. p. 28892. ISSN 2045-2322

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Abstract

Nα-acetylation is a naturally occurring irreversible modification of N-termini of proteins catalyzed by Nα-acetyltransferases (NATs). Although present in all three domains of life, it is little understood in bacteria. The functional grouping of NATs into six types NatA - NatF, in eukaryotes is based on subunit requirements and stringent substrate specificities. Bacterial orthologs are phylogenetically divergent from eukaryotic NATs, and only a couple of them are characterized biochemically. Accordingly, not much is known about their substrate specificities. Rv3420c of Mycobacterium tuberculosis is a NAT ortholog coding for RimI(Mtb). Using in vitro peptide-based enzyme assays and mass-spectrometry methods, we provide evidence that RimI(Mtb) is a protein Nα-acetyltransferase of relaxed substrate specificity mimicking substrate specificities of eukaryotic NatA, NatC and most competently that of NatE. Also, hitherto unknown acetylation of residues namely, Asp, Glu, Tyr and Leu by a bacterial NAT (RimI(Mtb)) is elucidated, in vitro. Based on in vivo acetylation status, in vitro assay results and genetic context, a plausible cellular substrate for RimI(Mtb) is proposed.

Item Type:	Article
Additional Information:	Open Access
Uncontrolled Keywords:	Mycobacterium tuberculosis; Bioinformatics
Subjects:	Q Science > QR Microbiology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	29 Sep 2016 07:18
Last Modified:	29 Sep 2016 07:18
URI:	http://crdd.osdd.net/open/id/eprint/1895

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