Mode of action of closthioamide: the first member of the polythioamide class of bacterial DNA gyrase inhibitors
Mode of action of closthioamide: the first member of the polythioamide class of bacterial DNA gyrase inhibitors
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DOI：
10.1093/jac/dkv161
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发表时间：
2015-09-01
影响因子：
5.2
通讯作者：
Sahl, Hans-Georg
中科院分区：
文献类型：
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作者：
Chiriac, Alina Iulia;Kloss, Florian;Sahl, Hans-Georg
目的：MDR细菌的传播代表了对人类社会的严重威胁，迫切需要新的抗生素药物，优选来自新的化学类别。Closthioamide是从严格厌氧细菌Clostridium cellulolyticum中分离得到的一种新型天然产物，聚硫代酰胺。在这里，我们研究了closthioamide的抗菌活性和作用机制。方法：为了评估closthioamide的抗菌活性，测定MIC值和杀灭动力学。为了鉴定其靶途径，使用基于全细胞的测定，包括分析大分子合成和记录具有下调的潜在靶基因的克隆库的易感性概况。随后，closthioamide对分离的靶酶，如DNA促旋酶和拓扑异构酶IV的活性的抑制作用进行了评估。值得注意的是，氯硫代酰胺对MRSA和VRE菌株非常有效。Closthioamide损害DNA复制和抑制DNA促旋酶的活性，特别是ATP酶的促旋酶和拓扑异构酶IV的功能，而有一点影响的切割重连接功能。Closthioamide也抑制DNA促旋酶的松弛活性，这不需要ATP水解，因此可能是变构的，而不是直接干扰促旋酶的ATP酶活性。交叉耐药环丙沙星和新生霉素不能检测到在实验突变体和临床分离株。结论：Closthioamide，一个前所未有的一类抗生素的成员，是一种有效的细菌DNA旋转酶抑制剂，但其分子机制不同于喹诺酮类和氨基香豆素类。
Objectives: The spread of MDR bacteria represents a serious threat to human society and novel antibiotic drugs, preferably from new chemical classes, are urgently needed. Closthioamide was isolated from the strictly anaerobic bacterium Clostridium cellulolyticum and belongs to a new class of natural products, the polythioamides. Here, we investigated the antimicrobial activity and mechanism of action of closthioamide.Methods: For assessing the antimicrobial activity of closthioamide, MIC values and killing kinetics were determined. To identify its target pathway, whole-cell-based assays were used including analysis of macromolecular synthesis and recording the susceptibility profile of a library of clones with down-regulated potential target genes. Subsequently, the inhibitory effect of closthioamide on the activity of isolated target enzymes, e.g. DNA gyrase and topoisomerase IV, was evaluated.Results: Closthioamide had broad-spectrum activity against Gram-positive bacteria. Notably, closthioamide was very potent against MRSA and VRE strains. Closthioamide impaired DNA replication and inhibited DNA gyrase activity, in particular the ATPase function of gyrase and of topoisomerase IV, whereas there was little effect on the cleavage-rejoining function. Closthioamide also inhibited the relaxation activity of DNA gyrase, which does not require ATP hydrolysis, and thus may allosterically rather than directly interfere with the ATPase activity of gyrase. Cross-resistance to ciprofloxacin and novobiocin could not be detected in experimental mutants and clinical isolates.Conclusions: Closthioamide, a member of an unprecedented class of antibiotics, is a potent inhibitor of bacterial DNA gyrase; however, its molecular mechanism differs from that of the quinolones and aminocoumarins.