Bloch M A, Raibaud O
J Bacteriol. 1986 Dec;168(3):1220-7. doi: 10.1128/jb.168.3.1220-1227.1986.
Using the mini-Mu-duction technique, we cloned the malA regions from Escherichia coli K-12 and Klebsiella pneumoniae. A comparison of the structures of the cloned DNAs indicated that the malT, malP, and malQ genes, encoding the transcriptional activator of the maltose regulon, maltodextrin phosphorylase, and amylomaltase, respectively, are similarly organized in both species; malP and malQ constitute an operon divergent from the malT gene. We sequenced 1,200 nucleotides encompassing the beginnings of the malT and malP genes, their promoters, and the intergenic region. The DNA sequences from the two species were very different; the levels of homology ranged from 28 to 80%, depending on the region. The sequences of the coding regions and of elements known to be important for the functions of these two promoters in E. coli were well conserved between the two bacteria, whereas the sequence of the malT-malP intergenic region had totally diverged.
我们使用微型 Mu 转导技术，从大肠杆菌 K-12 和肺炎克雷伯菌中克隆了 malA 区域。对克隆 DNA 结构的比较表明，分别编码麦芽糖操纵子转录激活因子、麦芽糊精磷酸化酶和淀粉麦芽糖酶的 malT、malP 和 malQ 基因在这两个物种中的组织方式相似；malP 和 malQ 构成了一个与 malT 基因不同的操纵子。我们对包含 malT 和 malP 基因起始部分、它们的启动子以及基因间区域的 1200 个核苷酸进行了测序。这两个物种的 DNA 序列差异很大；同源性水平在 28% 到 80% 之间，具体取决于区域。在这两种细菌之间，编码区的序列以及已知对大肠杆菌中这两个启动子功能很重要的元件的序列保守性良好，而 malT-malP 基因间区域的序列则完全不同。
