MTCC and Gene Bank, CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh, 160036, India.
AMB Express. 2013 Jan 5;3(1):2. doi: 10.1186/2191-0855-3-2.
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.
从根际土壤样本中分离到一株能产生两种抗菌肽的细菌菌株，并根据表型和 16S rRNA 基因序列系统发育分析鉴定为枯草芽孢杆菌。该菌株在高达 14%的 NaCl 中生长最佳，在生长 24 小时内产生抗菌肽。采用化学提取和色谱技术相结合的方法对肽进行纯化。HPLC 纯化馏分的 MALDI-TOF 分析表明，该菌株 SK.DU.4 分泌了一种分子量为 5323.9 Da 的细菌素样肽和一种表面活性脂肽（m/z 1056 Da）。低分子量细菌素的肽质量指纹图谱与分泌性脂蛋白的伸展具有显著的相似性甲基单胞菌 BG8 和显示 70%的序列覆盖率。MALDI MS/MS 分析将脂肽鉴定为一种β-羟基脂肪酸与肽中 Ser 相连的环状脂肽，该肽具有七个α-氨基酸（Asp-Tyr-Asn-Gln-Pro-Asn-Ser），并将其分配到抗菌生物表面活性剂的iturin 样组中。然而，它与iturin 家族的其他成员在氨基酸组成上有所不同。两种肽都对革兰氏阳性菌有效，表明它们具有协同作用。
