Synthesis and Succinylation of Subtilin-Like Lantibiotics Are Strongly Influenced by Glucose and Transition State Regulator AbrB
Synthesis and Succinylation of Subtilin-Like Lantibiotics Are Strongly Influenced by Glucose and Transition State Regulator AbrB
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DOI：
10.1128/aem.02579-14
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发表时间：
2015-01-01
影响因子：
4.4
通讯作者：
Entian, Karl-Dieter
中科院分区：
文献类型：
--
作者：
Bochmann, Sophie M.;Spiess, Tobias;Entian, Karl-Dieter
枯草芽孢杆菌素（Subtilin）和与其密切相关的entianin是由枯草芽孢杆菌不同亚种产生的I类抗生素。这两种分子都是核糖体合成的具有不寻常环结构的肽抗生素。subtilin样lantibiotics对多种革兰氏阳性菌具有较强的抗菌活性，其抗菌效果与乳球菌中的nisin相似。与nisin相反，subtilin-like lantibiotics部分经历额外的翻译后修饰，其中n端色氨酸残基被琥珀酰化，导致抗生素活性急剧降低。基于高效液相色谱（HPLC）的高灵敏度定量方法使我们能够测定生长过程中上清液中entianin和琥珀酰化entianin （S-entianin）的浓度。我们发现，天门冬氨酸的合成和琥珀酰化程度随着培养条件的变化而急剧变化。特别是，葡萄糖浓度的增加导致陆基培养基中青果素含量的增加和s -青果素比例的降低。相比之下，在含有10%葡萄糖的培养基A中未观察到琥珀酰化。有趣的是，葡萄糖延缓了氨基酸生物合成基因的表达。此外，在含有10%葡萄糖的培养基a中，过渡状态调节因子AbrB的缺失导致田鸡苷产量增加6倍。这表明枯草芽孢杆菌中的天冬氨酸生物合成除了受到过渡状态调节因子AbrB的调控外，还受到葡萄糖的强烈影响。我们的研究结果表明，subtillin样l抗生素琥珀酰化的机制是酶催化的，发生在细胞外空间或细胞膜上。
Subtilin and the closely related entianin are class I lantibiotics produced by different subspecies of Bacillus subtilis. Both molecules are ribosomally synthesized peptide antibiotics with unusual ring structures. Subtilin-like lantibiotics develop strong antibiotic activities against various Gram-positive organisms with an efficiency similar to that of nisin from Lactococcus lactis. In contrast to nisin, subtilin-like lantibiotics partially undergo an additional posttranslational modification, where the N-terminal tryptophan residue becomes succinylated, resulting in drastically reduced antibiotic activities. A highly sensitive high-performance liquid chromatography (HPLC)-based quantification method enabled us to determine entianin and succinylated entianin (S-entianin) concentrations in the supernatant during growth. We show that entianin synthesis and the degree of succinylation drastically change with culture conditions. In particular, increasing glucose concentrations resulted in higher entianin amounts and lower proportions of S-entianin in Landy-based media. In contrast, no succinylation was observed in medium A with 10% glucose. Interestingly, glucose retarded the expression of entianin biosynthesis genes. Furthermore, deletion of the transition state regulator AbrB resulted in a 6-fold increased entianin production in medium A with 10% glucose. This shows that entianin biosynthesis in B. subtilis is strongly influenced by glucose, in addition to its regulation by the transition state regulator AbrB. Our results suggest that the mechanism underlying the succinylation of subtilin-like lantibiotics is enzymatically catalyzed and occurs in the extracellular space or at the cellular membrane.