M.H2I, A MULTISPECIFIC 5C-DNA METHYLTRANSFERASE ENCODED BY BACILLUS-AMYLOLIQUEFACIENS PHAGE-H2

Bacillus amyloliquefaciens phage H2 codes for a multispecific cytosine-5-DNA-methyltransferase (MTase), M.H2I, which methylates GGCC, GCNGC and [GRAPHICS] target sequences. The gene coding for M.H2I was cloned in Escherichia coli and its nucleotide (nt) sequence was determined. It consists of 1509 bp, corresponding to a protein of 503 amino acids (aa) with a calculated M(r) of 57166. A comparison of the aa sequence of M.H2I with those of the multispecific MTases encoded by Bacillus subtilis phages SPR, phi-3T and rho-11s, revealed that M.H2I is closely related to these enzymes. A very high degree of homology was observed between M.H2I and M.rho-11(s)I, with 96.2% aa identity and 97.8% nt identity of the corresponding genes.