Gassner C, Schneider-Scherzer E, Lottspeich F, Schweiger M, Auer B
Institute of Biochemistry, University of Innsbruck, Austria.
Biol Chem. 1998 Apr-May;379(4-5):621-3.
Infection of Escherichia coli cells with bacteriophage T1 induces synthesis of a bacteriophage-specific DNA methyltransferase (M.EcoT1, EC No: 2.1.1.72) with a specificity for adenine residues in the sequence 5'-GATC-3'. Purification of M.EcoT1 allowed the determination of the coding sequence of the gene (Schneider-Scherzer et al., 1990). The peptide of the entire coding sequence was over-expressed as a histidine-hexapeptide tagged protein in E. coli. Affinity purification using a Ni2+ chelating (Ni-NTA) resin yielded a recombinant enzyme with almost the same enzymatic properties as the protein purified from T1 infected E. coli cells. Interestingly, in both purification procedures, a protein with a molecular weight of 50000 was found to copurify with M.EcoT1. The N-terminal amino acid sequence identified these proteins in both cases as E. coli enolase (EC No: 4.2.1.11).
用噬菌体T1感染大肠杆菌细胞会诱导合成一种噬菌体特异性DNA甲基转移酶（M.EcoT1，酶学委员会编号：2.1.1.72），它对序列5'-GATC-3'中的腺嘌呤残基具有特异性。M.EcoT1的纯化使得该基因编码序列得以确定（施奈德 - 舍尔泽等人，1990年）。整个编码序列的肽段作为带有组氨酸六肽标签的蛋白质在大肠杆菌中过表达。使用Ni2+螯合（Ni-NTA）树脂进行亲和纯化得到了一种重组酶，其酶学性质与从T1感染的大肠杆菌细胞中纯化的蛋白质几乎相同。有趣的是，在这两种纯化过程中，都发现一种分子量为50000的蛋白质与M.EcoT1共纯化。N端氨基酸序列在这两种情况下都将这些蛋白质鉴定为大肠杆菌烯醇化酶（酶学委员会编号：4.2.1.11）。
