Bentley J, Hyatt L S, Ainley K, Parish J H, Herbert R B, White G R
Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Gene. 1993 May 15;127(1):117-20. doi: 10.1016/0378-1119(93)90625-d.
We have cloned and sequenced DNA from Escherichia coli that, when present in a high-copy-number plasmid, confers resistance to the diketopiperazine antibiotic, bicyclomycin (Bc). The DNA includes a 378-amino-acid open reading frame (ORF), disruption of which results in the loss of Bc resistance. This ORF contains the BcR gene. Studies using the minicell expression system reveal that a polypeptide of 31 kDa is produced from this cloned region. The ORF maps at 47.1 min on the E. coli genome map. Sequence comparison between the translated ORF and a protein database reveal between 26.5 and 23.4% aa sequence homology to bacterial transmembrane (TM) proteins including those mediating chloramphenicol (Cm) and tetracycline (Tc) resistance and an arabinose-proton symport protein. Sequence analysis using the Diagon program showed the BcR gene product (BcR) had homology with the N-terminal regions of the CmR and TcR-encoded proteins and weak N-terminal homology with the arabinose-proton symport protein. Hydropathy profiles of the BcR protein and CmR products show a striking similarity, both having twelve predicted TM domains.
我们已从大肠杆菌中克隆并测序了一段DNA，当它存在于高拷贝数质粒中时，可赋予对二酮哌嗪抗生素双环霉素（Bc）的抗性。该DNA包含一个378个氨基酸的开放阅读框（ORF），破坏此阅读框会导致Bc抗性丧失。这个ORF包含BcR基因。使用小细胞表达系统进行的研究表明，从该克隆区域产生了一种31 kDa的多肽。该ORF位于大肠杆菌基因组图谱的47.1分钟处。将翻译后的ORF与蛋白质数据库进行序列比较，发现与包括介导氯霉素（Cm）和四环素（Tc）抗性的那些以及阿拉伯糖 - 质子同向转运蛋白在内的细菌跨膜（TM）蛋白具有26.5%至23.4%的氨基酸序列同源性。使用Diagon程序进行的序列分析表明，BcR基因产物（BcR）与CmR和TcR编码蛋白的N端区域具有同源性，并且与阿拉伯糖 - 质子同向转运蛋白具有较弱的N端同源性。BcR蛋白和CmR产物的亲水性图谱显示出惊人的相似性，两者都有十二个预测的跨膜结构域。
