SEQUENCE OF THE GENE ENCODING A 2ND SCRFI M(5)C METHYLTRANSFERASE OF LACTOCOCCUS-LACTIS

The nucleotide (nt) sequence of a second methyltransferase (MTase)-enc oding gene associated with the ScrFI restriction/modification (R/M) sy stem (5'-CCNGG-3') of Lactococcus lactis ssp. cremoris UC503 has been determined. The coding region was 1080 nt in length and capable of spe cifying a 41847-Da protein of 360 amino acids (aa). The deduced aa seq uence displayed motifs characteristic of all prokaryotic 5-methylcytos ine (m(5)C) MTases. Significant similarity was observed with other m(5 )C MTases, apart from the variable region which has been deemed respon sible for target sequence specificity. A larger than normal spacing be tween motif II and motif III, comparable in length and bearing homolog y to a similar region in the SssI MTase, was observed. A second open r eading frame (ORF) of unknown function, which has the capacity to enco de a protein of 155 aa, was observed three nt upstream from the m(5)C MTase ORF.