Department of Chemical, Food, Pharmaceutical and Pharmacological Sciences (DiSCAFF), Drug and Food Biotechnology Centre, University of Eastern Piedmont, Via Bovio 6, 28100 Novara, Italy.
J Mass Spectrom. 2010 Jul;45(7):772-8. doi: 10.1002/jms.1767.
Lipopeptide biosurfactants produced by the Bacillus licheniformis V9T14 strain showed an interesting anti-adhesion activity against biofilm formation of human pathogenic bacterial strains. The chemical characterisation of the crude extract of V9T14 strain was first developed through electrospray ionisation mass spectrometry (ESI-MS) and ESI-MS/MS direct infusions: two sets of molecular ion species belonging to the fengycin and surfactin families were revealed and their structures defined, interpreting their product ion spectra. The LC/ESI-MS analysis of the crude extract allowed to separate in different chromatogram ranges the homologues and the isoforms of the two lipopeptide families. The extract was then fractionated by silica gel chromatography in two main fractions, I and II. The purified biosurfactants were analysed through a new, rapid and suitable LC/ESI-MS/MS method, which allowed characterising the composition and the structures of the produced lipopeptides. LC/ESI-MS/MS analysis of fraction I showed the presence of C(13), C(14) and C(15) surfactin homologues, whose structures were confirmed by the product ion spectra of the sodiated molecules M + Na at m/z 1030, 1044 and 1058. LC/ESI-MS/MS analysis of fraction II confirmed the presence of two main fengycin isoforms, with the protonated molecules M + H at m/z 1478 and 1506 corresponding to C(17) fengycin A and C(17) fengycin B, respectively. Other homologues (C(14) to C(16)) were revealed and confirmed as belonging to fengycin A or B according to the retention times and the product ions generated, although with the same nominal mass. Finally, a relative percentage content of each homologue for both lipopeptides families in the whole extract was proposed.
由地衣芽孢杆菌 V9T14 菌株产生的脂肽生物表面活性剂对人病原菌生物膜形成表现出有趣的抗黏附活性。通过电喷雾电离质谱（ESI-MS）和 ESI-MS/MS 直接进样，首先对 V9T14 菌株的粗提物进行了化学表征：揭示了两组属于丰原素和表面活性剂家族的分子离子物种，并对其结构进行了定义，解释了它们的产物离子谱。粗提物的 LC/ESI-MS 分析允许将两种脂肽家族的同系物和同型物在不同的色谱图范围内分离。然后，通过硅胶色谱将提取物分为两大部分，I 和 II。通过一种新的、快速且合适的 LC/ESI-MS/MS 方法对纯化的生物表面活性剂进行分析，该方法允许对产生的脂肽的组成和结构进行表征。I 部分的 LC/ESI-MS/MS 分析表明存在 C(13)、C(14)和 C(15)表面活性剂同系物，其结构通过加钠离子的分子M+Na在 m/z 1030、1044 和 1058 的产物离子谱得到确认。II 部分的 LC/ESI-MS/MS 分析证实存在两种主要的丰原素同型物，质子化分子M+H在 m/z 1478 和 1506 处分别对应于 C(17)丰原素 A 和 C(17)丰原素 B。根据保留时间和生成的产物离子，还揭示并确认了其他同系物（C(14)至 C(16)）属于丰原素 A 或 B，尽管它们的分子量相同。最后，提出了两种脂肽家族在整个提取物中的每个同系物的相对百分比含量。
