Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample.

Baindara, Piyush and Mandal, Santi M and Chawla, Niharika and Singh, Pradip Kumar and Pinnaka, Anil Kumar and Korpole, Suresh (2013) Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample. AMB Express, 3 (1). p. 2. ISSN 2191-0855

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Abstract

A bacterial strain producing two antimicrobial peptides was isolated from a rhizosphere soil sample and identified as Bacillus subtilis based on both phenotypic and 16S rRNA gene sequence phylogenetic analysis. It grew optimally up to 14% NaCl and produced antimicrobial peptide within 24 h of growth. The peptides were purified using a combination of chemical extraction and chromatographic techniques. The MALDI-TOF analysis of HPLC purified fractions revealed that the strain SK.DU.4 secreted a bacteriocin-like peptide with molecular mass of 5323.9 Da and a surface-active lipopeptide (m/z 1056 Da). The peptide mass fingerprinting of low-molecular-weight bacteriocin exhibited significant similarity with stretches of secreted lipoprotein of Methylomicrobium album BG8 and displayed 70% sequence coverage. MALDI MS/MS analysis elucidated the lipopeptide as a cyclic lipopeptide with a β-hydroxy fatty acid linked to Ser of a peptide with seven α-amino acids (Asp-Tyr-Asn-Gln-Pro-Asn-Ser) and assigned it to iturin-like group of antimicrobial biosurfactants. However, it differed in amino acid composition with other members of the iturin family. Both peptides were active against Gram-positive bacteria, suggesting that they had an additive effect.

Item Type:	Article
Additional Information:	Open Access
Uncontrolled Keywords:	Bacillus; Antimicrobial peptide; Lipopeptide; Chromatography; RP-HPLC; MALDI
Subjects:	Q Science > QR Microbiology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	24 Jun 2013 10:53
Last Modified:	24 Jun 2013 10:53
URI:	http://crdd.osdd.net/open/id/eprint/1306

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