Cain B D, Norton P J, Eubanks W, Nick H S, Allen C M
Department of Biochemistry and Molecular Biology, University of Florida, Gainesville 32610.
J Bacteriol. 1993 Jun;175(12):3784-9. doi: 10.1128/jb.175.12.3784-3789.1993.
An Escherichia coli genomic library was constructed in order to facilitate selection for genes which confer bacitracin resistance through amplification. One of the plasmids from the library, plasmid pXV62, provided a high level of bacitracin resistance for E. coli. Deletion and nucleotide sequence analyses of bacitracin resistance plasmid pXV62 revealed that a single open reading frame, designated the bacA gene, was sufficient for antibiotic resistance. The bacA gene mapped to approximately 67 min on the E. coli chromosome by proximity to a previously mapped locus. The deduced amino acid sequence of the bacA-encoded protein suggests an extremely hydrophobic protein of 151 amino acids, approximately 65% of which were nonpolar amino acids. E. coli cells containing plasmid pXV62 have increased isoprenol kinase activity. The physical characteristics of the deduced protein and enhanced lipid kinase activity suggest that the bacA gene may confer resistance to bacitracin by phosphorylation of undecaprenol.
构建了一个大肠杆菌基因组文库，以便通过扩增筛选出赋予杆菌肽抗性的基因。该文库中的一个质粒，即质粒pXV62，为大肠杆菌提供了高水平的杆菌肽抗性。对杆菌肽抗性质粒pXV62的缺失和核苷酸序列分析表明，一个单一的开放阅读框，命名为bacA基因，足以赋予抗生素抗性。通过与先前定位的基因座相邻，bacA基因定位在大肠杆菌染色体上大约67分钟处。bacA编码蛋白的推导氨基酸序列表明它是一种由151个氨基酸组成的极具疏水性的蛋白质，其中约65%为非极性氨基酸。含有质粒pXV62的大肠杆菌细胞具有增强的异戊烯醇激酶活性。推导蛋白的物理特性和增强的脂质激酶活性表明，bacA基因可能通过对十一异戊烯醇的磷酸化赋予对杆菌肽的抗性。
