Schneider A, Marahiel M A
Biochemie, Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
Arch Microbiol. 1998 May;169(5):404-10. doi: 10.1007/s002030050590.
Next to almost all prokaryotic operons encoding peptide synthetases, which are involved in the nonribosomal synthesis of peptide antibiotics, distinct genes have been detected that encode proteins with strong sequence similarity to type II fatty acid thioesterases of vertebrate origin. Furthermore, sequence analysis of bacterial and fungal peptide synthetases has revealed a region at the C-terminal end of modules that are responsible for adding the last amino acid to the peptide antibiotics; that region also exhibits significant similarities to thioesterases. In order to investigate the function of these putative thioesterases in non-ribosomal peptide synthesis of the lipopeptide antibiotic surfactin in Bacillus subtilis, srfA fragments encoding the thioesterase domain of the surfactin synthetase 3 and the thioesterase-like protein SrfA-TE were deleted. This led to a 97 and 84% reduction of the in vivo surfactin production, respectively. In the double mutant, however, no surfaction production was detectable. These findings demonstrate for the first time that the C-terminal thioesterase domains and the SrfA-TE protein are directly involved in nonribosomal peptide biosynthesis.
几乎所有编码肽合成酶的原核操纵子都与肽抗生素的非核糖体合成有关，在其旁边已检测到一些独特的基因，这些基因编码的蛋白质与脊椎动物来源的II型脂肪酸硫酯酶具有很强的序列相似性。此外，对细菌和真菌肽合成酶的序列分析揭示了模块C末端的一个区域，该区域负责将最后一个氨基酸添加到肽抗生素中；该区域也与硫酯酶表现出显著的相似性。为了研究这些假定的硫酯酶在枯草芽孢杆菌脂肽抗生素表面活性素的非核糖体肽合成中的功能，编码表面活性素合成酶3硫酯酶结构域和硫酯酶样蛋白SrfA-TE的srfA片段被删除。这分别导致体内表面活性素产量降低了97%和84%。然而，在双突变体中，未检测到表面活性素的产生。这些发现首次证明C末端硫酯酶结构域和SrfA-TE蛋白直接参与非核糖体肽生物合成。
