ESCHERICHIA-COLI BACTERIOPHAGE-T1 DNA METHYLTRANSFERASE APPEARS TO INTERACT WITH ESCHERICHIA-COLI ENOLASE

Infection of Escherichia coli cells with bacteriophage T1 induces synt hesis of a bacteriophage-specific DNA methyltransferase (M.EcoT1, EC N o: 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 cod ing sequence of the gene (Schneider-Scherzer et al., 1990). The peptid e of the entire coding sequence was over-expressed as a histidine-hexa peptide tagged protein in E. coli. Affinity purification using a Ni2chelating (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. T he N-terminal amino acid sequence identified these proteins in both ca ses as E. coli enolase (EC No: 4.2.1.11).