Köck J, Olschläger T, Kamp R M, Braun V
J Bacteriol. 1987 Jul;169(7):3358-61. doi: 10.1128/jb.169.7.3358-3361.1987.
The DNA sequence of the colicin M activity gene cma was determined. A polypeptide consisting of 271 amino acids was deduced from the nucleotide sequence. The amino acid sequence agreed with the peptide sequences determined from the isolated colicin. The molecular weight of active colicin M was 29,453. The primary translation product was not processed. In the domain required for uptake into cells, colicin M contained the pentapeptide Glu-Thr-Leu-Thr-Val. A similar sequence was found in all colicins which are taken up by a TonB-dependent mechanism and in outer membrane receptor proteins which are constituents of TonB-dependent transport systems. The structure of colicin M in the carboxy-terminal activity domain had no resemblance to the pore-forming colicins or colicins with endonuclease activity. Instead, the activity domain contained a sequence which exhibited homology to the sequence around the serine residue in the active site of penicillin-binding proteins of Escherichia coli. The colicin M activity gene was regulated from an SOS box upstream of the adjacent colicin B activity gene on the natural plasmid pColBM-Cl139.
测定了大肠杆菌素M活性基因cma的DNA序列。从核苷酸序列推导得出一个由271个氨基酸组成的多肽。该氨基酸序列与从分离出的大肠杆菌素测定的肽序列一致。活性大肠杆菌素M的分子量为29453。初级翻译产物未经过加工。在进入细胞所需的结构域中，大肠杆菌素M含有五肽Glu-Thr-Leu-Thr-Val。在所有通过依赖TonB的机制被摄取的大肠杆菌素以及作为依赖TonB的转运系统组成成分的外膜受体蛋白中都发现了类似序列。大肠杆菌素M在羧基末端活性结构域的结构与形成孔道的大肠杆菌素或具有核酸内切酶活性的大肠杆菌素没有相似之处。相反，活性结构域包含一个与大肠杆菌青霉素结合蛋白活性位点丝氨酸残基周围序列具有同源性的序列。大肠杆菌素M活性基因由天然质粒pColBM-Cl139上相邻的大肠杆菌素B活性基因上游的一个SOS框调控。
