Structural characterization of lacticin 3147, a two-peptide lantibiotic with synergistic activity
Structural characterization of lacticin 3147, a two-peptide lantibiotic with synergistic activity
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DOI：
10.1021/bi0362065
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发表时间：
2004-03-23
期刊：
影响因子：
2.9
通讯作者：
Vederas, JC
中科院分区：
文献类型：
--
作者：
Martin, NI;Sprules, T;Vederas, JC
羊毛硫抗生素是从细菌来源中分离出来的抗菌肽，对革兰氏阳性菌具有活性，通常比青霉素等传统抗生素有效几个数量级。它们含有许多独特的结构特征，包括脱氢氨基酸和羊毛硫氨酸（硫醚）残基。这些部分是在母体肽的核糖体翻译后引入的，使得传统的肽分析方法无效。我们在此报告了一种在氘气存在下使用硼化镍 (Ni2B) 来减少脱氢侧链并对羊毛硫抗生素中发现的羊毛硫氨酸桥进行还原脱硫的新方法。使用这种方法，可以通过传统的肽测序（埃德曼降解）和质谱分析来识别和区分脱氢侧链和羊毛硫氨酸桥的原始位置。该策略最初使用乳链菌肽 A（一种结构良好的羊毛硫抗生素）进行了验证，随后扩展到由乳酸乳球菌乳酸亚种 DPC3147 产生的新型双组分羊毛硫抗生素乳酸菌素 3147。然后，通过使用多维核磁共振波谱法对两种乳酸菌素 3147 肽的一级结构进行了完全鉴定，表明乳酸菌素 3147 A1 具有特定的羊毛硫氨酸桥接模式，类似于球状 B 型羊毛硫抗生素 Meracidin，而 A2 肽是细长的 A 型羊毛硫抗生素类的成员。通过NMR还获得了两种乳酸菌素3147肽的溶液构象，表明A1可能采用与美西丁相似的构象，而A2肽采用α-螺旋结构。这些结果是协同羊毛硫抗生素对的首次结果（迄今为止仅报道了四对这样的对）。
Lantibiotics are antibacterial peptides isolated from bacterial sources that exhibit activity toward Gram-positive organisms and are usually several orders of magnitude more potent than traditional antibiotics such as penicillin. They contain a number of unique structural features including dehydro amino acid and lanthionine (thioether) residues. Introduced following ribosomal translation of the parent peptide, these moieties render conventional methods of peptide analysis ineffective. We report herein a new method using nickel boride (Ni2B), in the presence of deuterium gas, to reduce dehydro side chains and reductively desulfurize lanthionine bridges found in lantibiotics. Using this approach, it is possible to identify and distinguish the original locations of dehydro side chains and lanthionine bridges by traditional peptide sequencing (Edman degradation) followed by mass spectrometry. The strategy was initially verified using nisin A, a structurally well characterized lantibiotic, and subsequently extended to the novel two-component lantibiotic, lacticin 3147, produced by Lactococcus lactis subspecies lactis DPC3147. The primary structures of both lacticin 3147 peptides were then fully assigned by use of multidimensional NMR spectroscopy, showing that lacticin 3147 A1 has a specific lanthionine bridging pattern which resembles the globular type-B lantibiotic mersacidin, whereas the A2 peptide is a member of the elongated type-A lantibiotic class. Also obtained by NMR were solution conformations of both lacticin 3147 peptides, indicating that A1 may adopt a conformation similar to that of mersacidin and that the A2 peptide adopts a-helical structure. These results are the first of their kind for a synergistic lantibiotic pair (only four such pairs have been reported to date).