Site-Directed Mutations in the Lanthipeptide Mutacin 1140
Site-Directed Mutations in the Lanthipeptide Mutacin 1140
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DOI：
10.1128/aem.00704-13
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发表时间：
2013-07-01
影响因子：
4.4
通讯作者：
Smith, Leif
中科院分区：
文献类型：
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作者：
Chen, Shaorong;Wilson-Stanford, Shawanda;Smith, Leif
口腔细菌变形链球菌菌株JH 1140产生抗生素mutacin 1140。Mutacin 1140属于一组称为羊毛硫肽的抗生素。更具体地说，突变蛋白1140与表皮蛋白A型（I）羊毛硫肽相关。这组羊毛硫肽的诱变实验主要限于后修饰的内消旋羊毛硫肽和3-甲基羊毛硫肽残基。使用自杀载体pVA 891进行突变蛋白1140的核心肽的定点诱变。研究了N末端残基、铰链区带电残基以及A环和交织环C和D中残基的取代。还进行了环A和缠结环C和D中残基的截短和插入，以确定它们是否会改变生产菌株的抗微生物活性。生物测定显示，研究的14个突变体中有5个对指示菌株藤黄微球菌ATCC 10240具有改善的抗微生物活性。测定了三种突变蛋白1140变体对变形链球菌UA 159、肺炎链球菌ATCC 27336、金黄色葡萄球菌ATCC 25923、艰难梭菌UK 1和藤黄微球菌ATCC 10240的MIC，这些变体在M.黄体生物测定这项对羊毛硫肽表皮素组的突变研究表明，抗微生物活性可以显着提高。
The oral bacterium Streptococcus mutans, strain JH1140, produces the antibiotic mutacin 1140. Mutacin 1140 belongs to a group of antibiotics called lanthipeptides. More specifically, mutacin 1140 is related to the epidermin type A(I) lanthipeptides. Mutagenesis experiments of this group of lanthipeptides have been primarily restricted to the posttranslationally modified meso-lanthionine and 3-methyllanthionine residues. Site-directed mutagenesis of the core peptide of mutacin 1140 was performed using the suicide vector pVA891. Substitutions of the N-terminal residue, the charged residue in the hinge region, and residues in ring A and intertwined rings C and D were investigated. A truncation and insertion of residues in ring A and intertwined rings C and D were also performed to determine whether or not they would alter the antimicrobial activity of the producing strain. Bioassays revealed that five of 14 mutants studied had improved antimicrobial activity against the indicator strain Micrococcus luteus ATCC 10240. MICs against Streptococcus mutans UA159, Streptococcus pneumoniae ATCC 27336, Staphylococcus aureus ATCC 25923, Clostridium difficile UK1, and Micrococcus luteus ATCC 10240 were determined for three mutacin 1140 variants that had the most significant increases in bioactivity in the M. luteus bioassay. This mutagenesis study of the epidermin group of lanthipeptides shows that antimicrobial activity can be significantly improved.