Shpakovskiĭ G V, Akhrem A A, Berlin Iu A
Bioorg Khim. 1986 May;12(5):695-8.
In studying molecular mechanisms of specialized transduction, primary structure of the junction between the E. coli gene lacI and the lambda phage locus Ea47 in transducing bacteriophage lambda plac5 has been established. Along with the lambda DNA and E. coli lac operon structures as well as with our earlier data on another phage-bacterial junction in lambda plac5, it lead to the complete sequence of lambda plac5 DNA, including the lac5 substitution, a wellknown segment of lambdoid cloning vehicles. The lambda plac5 DNA is shown to consist of 48645 b.p. distributed as follows: 19368 (lambda left arm) + 3924 (lac5 substitution) + 25353 (lambda right arm). The presence of the phage pbL promoter near to the right end of the lac5 insert is shown. The lacI gene distal end in lambda plac5 proved to be considerably more long-stretched than it used to be believed, coding for 224 C-terminal amino-acid residues of lac repressor. The recombination studied in this paper, similarly to the abnormal prophage excision, occurred near to a Chi-like structure, which is partly homologous to the chi+lacZ site present in lambda plac5. On the basis of the data obtained, a key role of the E. coli RecBC system and Chi sites in the formation of long-stretched deletions in the bacterial cell has been suggested.
在研究特异性转导的分子机制时，已经确定了转导噬菌体λplac5中大肠杆菌基因lacI与λ噬菌体基因座Ea47之间连接的一级结构。结合λDNA和大肠杆菌lac操纵子结构以及我们之前关于λplac5中另一个噬菌体 - 细菌连接的数据，得出了λplac5 DNA的完整序列，包括lac5替换，这是λ类克隆载体的一个著名片段。λplac5 DNA显示由48645个碱基对组成，分布如下：19368（λ左臂）+ 3924（lac5替换）+ 25353（λ右臂）。显示在lac5插入片段右端附近存在噬菌体pbL启动子。λplac5中的lacI基因远端比过去认为的长得多，编码lac阻遏物的224个C端氨基酸残基。本文研究的重组与异常原噬菌体切除类似，发生在一个类似Chi的结构附近，该结构与λplac5中存在的chi + lacZ位点部分同源。根据获得的数据，提出了大肠杆菌RecBC系统和Chi位点在细菌细胞中长延伸缺失形成中的关键作用。
