The peptide antibiotic microcin B17 induces double‐strand cleavage of DNA mediated by E. coli DNA gyrase.
The peptide antibiotic microcin B17 induces double‐strand cleavage of DNA mediated by E. coli DNA gyrase.
复制标题
肽类抗生素小菌素 B17 可诱导大肠杆菌 DNA 旋转酶介导的 DNA 双链切割。
作者：
J. L. Vizán;C. Hernández‐Chico;I. D. Castillo;Felipe Moreno
Microcin B17（MccB 17）是一种杀菌肽抗生素，可抑制DNA复制。分离出两个大肠杆菌MccB 17抗性突变体，并显示突变映射到83 min的遗传图谱。突变的克隆和Tn 5插入分析表明它们位于gyrB内。作为测序的前一步，通过构建杂交基因来确定gyrB内突变的大致位置。这两种突变均由基因第2251位的单个AT-GC转换组成，其在GyrB多肽的氨基酸序列中产生Trp 751-Arg取代。测定MccB 17对复制性无细胞提取物的抑制作用。在该体外系统中，MccB 17与提取物组分的相互作用诱导质粒DNA的双链切割。用MccB 17进行体内处理也会诱导染色体DNA上明确的切割模式。在MccB 17耐药gyrB突变体中未观察到这些效应。总之，我们的结果表明MccB 17通过捕获酶-DNA可切割复合物来阻断DNA促旋酶。因此，这种肽抗生素的作用模式类似于喹诺酮类和目前用于癌症化疗的各种抗肿瘤药物。MccB 17是第一个显示出抑制II型DNA拓扑异构酶的肽。
Microcin B17 (MccB17) is a bactericidal peptide antibiotic which inhibits DNA replication. Two Escherichia coli MccB17 resistant mutants were isolated and the mutations were shown to map to 83 min of the genetic map. Cloning of the mutations and Tn5 insertional analysis demonstrated that they were located inside gyrB. The approximate location of the mutations within gyrB was determined by constructing hybrid genes, as a previous step to sequencing. Both mutations were shown to consist of a single AT‐‐‐‐GC transition at position 2251 of the gene, which produces a Trp751‐‐‐‐Arg substitution in the amino acid sequence of the GyrB polypeptide. The inhibitory effect of MccB17 on replicative cell‐free extracts was assayed. In this in vitro system, interaction of MccB17 with a component of the extracts induced double‐strand cleavage of plasmid DNA. In vivo treatment with MccB17 also induced a well‐defined cleavage pattern on chromosomal DNA. These effects were not observed with a MccB17‐resistant, gyrB mutant. Altogether, our results indicate that MccB17 blocks DNA gyrase by trapping an enzyme‐DNA cleavable complex. Thus, the mode of action of this peptide antibiotic resembles that of quinolones and a variety of antitumour drugs currently used in cancer chemotherapy. MccB17 is the first peptide shown to inhibit a type II DNA topoisomerase.
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T4 DNA 拓扑异构酶的 52 个蛋白亚基与促旋酶的 gyrA 蛋白同源。
影响因子：
14.9
作者：
Huang,WM
通讯作者：
Huang,WM
II 型 DNA 拓扑异构酶基因的核苷酸序列。
影响因子：
14.9
作者：
Huang,WM
通讯作者：
Huang,WM
影响因子：
56.9
作者：
TEWEY, KM;ROWE, TC;LIU, LF
通讯作者：
LIU, LF
影响因子：
5.6
作者：
WYCKOFF, E;NATALIE, D;HSIEH, TS
通讯作者：
HSIEH, TS
DNA 旋转酶与原核重复基因外回文序列家族结合。
DOI：
10.1073/pnas.85.23.8850
发表时间：
1988
影响因子：
11.1
作者：
Yang,Y;Ames,GF
通讯作者：
Ames,GF