Catchpole I, Thomas C, Davies A, Dyke K G
Department of Biochemistry, University of Oxford, UK.
J Gen Microbiol. 1988 Mar;134(3):697-709. doi: 10.1099/00221287-134-3-697.
The complete nucleotide sequence of a naturally occurring Staphylococcus aureus plasmid, pT48 (from S. aureus strain T48), has been determined. The 2475 bp plasmid confers inducible resistance to macrolide-lincosamide-streptogramin B (MLS) type antibiotics. It is similar to the constitutive MLS resistance plasmid, pNE131, from Staphylococcus epidermidis and shows homology with S. aureus plasmids pSN2 and pE194. It contains a palA structure homologous to that on S. aureus plasmid pT181. The open reading frame, ORF B, within the pSN2 homologous region has a frameshifted C-terminus, relative to pNE131, resulting in a smaller, 158 amino acid putative polypeptide. The pE194 homologous region has the ermC resistance determinant and retains the leader region, deleted in pNE131, required for inducible expression of an adenine methylase. Another naturally occurring S. aureus strain, J74, shows constitutive resistance to erythromycin and contains a small plasmid, pJ74, which is similar to pNE131 but with a different deletion in the leader sequence. The results are consistent with the translational attenuation model for ermC expression.
已确定一株天然存在的金黄色葡萄球菌质粒pT48（来自金黄色葡萄球菌菌株T48）的完整核苷酸序列。这个2475 bp的质粒赋予对大环内酯 - 林可酰胺 - 链阳霉素B（MLS）类抗生素的诱导型抗性。它与来自表皮葡萄球菌的组成型MLS抗性质粒pNE131相似，并与金黄色葡萄球菌质粒pSN2和pE194显示出同源性。它含有一个与金黄色葡萄球菌质粒pT181上的palA结构同源的结构。相对于pNE131，pSN2同源区域内的开放阅读框ORF B具有移码的C末端，导致产生一个较小的、158个氨基酸的推定多肽。pE194同源区域具有ermC抗性决定簇，并保留了pNE131中缺失的前导区域，该区域是腺嘌呤甲基化酶诱导表达所必需的。另一株天然存在的金黄色葡萄球菌菌株J74对红霉素表现出组成型抗性，并含有一个小质粒pJ74，它与pNE131相似，但前导序列中有不同的缺失。这些结果与ermC表达的翻译衰减模型一致。
