Sequential actions of the two component peptides of the lantibiotic lacticin 3147 explain its antimicrobial activity at nanomolar concentrations
Sequential actions of the two component peptides of the lantibiotic lacticin 3147 explain its antimicrobial activity at nanomolar concentrations
复制标题
DOI：
10.1128/aac.49.7.2606-2611.2005
复制
发表时间：
2005-07-01
影响因子：
4.9
通讯作者：
Hill, C
中科院分区：
文献类型：
--
作者：
Morgan, SM;O'Connor, PM;Hill, C
Lacticin 3147是由乳酸乳球菌乳酸亚种（Lactococcus lactis subsp.）lactis DPC 3147，并对所有测试的革兰氏阳性微生物具有抑制活性。在这项研究中，组分肽（单独或组合）的比活性通过使用L. lactis subsp. Cremoris HP为目标菌株。Lacticin 3147对各组分肽（组合）的MIC 50为7 nM，表明肽化学计量比为1：1。有趣的是，LtnA 1肽表现出独立的抑制活性，对L.乳酸菌在平行研究中，单肽细菌素乳链菌肽对相同的靶菌株表现出50 nM的MIC 50。顺序肽添加（具有中间洗涤步骤）证明必须在LtnA 2之前添加LtnA 1，而不是相反，以观察抑制活性。乳酸肽的纳摩尔活性表明参与了对接分子，推测为脂质II。结合最近确定的乳酸菌素3147（N.I.马丁，T. Sprules，M. R.卡彭特警察局科特角希尔河，巴西-地P. Ross和J.C. Vederas，Biochemistry，43：3049-3056，2004），这些数据支持以下假设：乳酸菌素3147的作用模式涉及脂质II结合步骤（通过mersacidin样LtnA 1肽，这将解释其独立的抑制活性），随后将更线性的LtnA 2肽插入靶膜，导致孔形成和最终的细胞死亡。
Lacticin 3147 is a two-peptide (LtnA1 and LtnA2) lantibiotic produced by Lactococcus lactis subsp. lactis DPC3147 and has inhibitory activity against all gram-positive microorganisms tested. In this study the specific activities of the component peptides (alone or in combination) were determined by using L. lactis subsp. cremoris HP as the target strain. Lacticin 3147 exhibited an MIC50 of 7 nM for each component peptide (in combination), suggesting a peptide stoichiometry of 1:1. Interestingly, the LtnA1 peptide demonstrated independent inhibitory activity, with an MIC50 of 200 nM against L. lactis HP. In parallel studies, the single peptide bacteriocin nisin exhibited an MIC50 of 50 nM against the same target strain. Sequential peptide addition (with an intermediate washing step) demonstrated that LtnA1 must be added before LtnA2 rather than vice versa to observe inhibitory activity. The nanomolar activity of the lacticin peptides suggests the involvement of a docking molecule, speculated to be lipid II. Taken together with the recently determined structure of lacticin 3147 (N.I. Martin, T. Sprules, M. R. Carpenter, P. D. Cotter, C. Hill, R. P. Ross, and J.C. Vederas, Biochemistry, 43:3049-3056, 2004), these data support the hypothesis that the mode of action for lacticin 3147 involves a lipid II binding step (by the mersacidin-like LtnA1 peptide, which would explain its independent inhibitory activity), followed by insertion of the more linear LtnA2 peptide into the target membrane, resulting in pore formation and ultimate cell death.