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首页> 外文期刊>Journal of bacteriology >Molecular analysis of a beta-lactam resistance gene encoded within the cephamycin gene cluster of Streptomyces clavuligerus.
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Molecular analysis of a beta-lactam resistance gene encoded within the cephamycin gene cluster of Streptomyces clavuligerus.

机译：克拉维链霉菌的头霉素基因簇内编码的β-内酰胺抗性基因的分子分析。

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A Streptomyces clavuligerus gene (designated pcbR) which is located immediately downstream from the gene encoding isopenicillin N synthase in the cephamycin gene cluster was characterized. Nucleotide sequence analysis and database searching of PcbR identified a significant similarity between PcbR and proteins belonging to the family of high-molecular-weight group B penicillin-binding proteins (PBPs). Eight of nine boxes (motifs) conserved within this family of proteins are present in the PcbR protein sequence in the same order and with approximately the same spacing between them. When a mutant disrupted in pcbR was constructed by gene replacement, the resulting pcbR mutant exhibited a significant decrease in its resistance to benzylpenicillin and cephalosporins, indicating that pcbR is involved in beta-lactam resistance in this organism. Western blot (immunoblot) analysis of S. clavuligerus cell membranes using PcbR-specific antibodies suggested that PcbR is a membrane protein. PcbR was also present in cell membranes when expressed in Escherichia coli and was able to bind radioactive penicillin in a PBP assay, suggesting that PcbR is a PBP. When genomic DNAs from several actinomycetes were probed with pcbR, hybridization was observed to some but not all beta-lactam-producing actinomycetes.
机译：表征了在头霉素基因簇中紧接编码异青霉素N合酶的基因下游的链霉菌棒状链霉菌基因（命名为pcbR）。 PcbR的核苷酸序列分析和数据库搜索确定了PcbR与属于高分子量B组青霉素结合蛋白（PBPs）家族的蛋白之间存在显着相似性。在该蛋白家族中保守的九个盒（基序）中的八个以相同的顺序并以大约相同的间距存在于PcbR蛋白序列中。当通过基因替换构建了pcbR破坏的突变体时，所得的pcbR突变体对苄青霉素和头孢菌素的耐药性显着降低，表明pcbR参与了该生物的β-内酰胺耐药性。使用PcbR特异性抗体对锁骨链球菌细胞膜进行蛋白质印迹（免疫印迹）分析表明，PcbR是一种膜蛋白。当在大肠杆菌中表达时，PcbR也存在于细胞膜中，并且能够在PBP分析中结合放射性青霉素，表明PcbR是PBP。当用pcbR探测来自几个放线菌的基因组DNA时，观察到与一些但不是全部产生β-内酰胺的放线菌的杂交。

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