title: Sequential order of target-recognizing domains in multispecific DNA-methyltransferases.
abstract: In the multispecific DNA(cytosine-5)-methyltransferases (Mtases) of Bacillus subtilis phages SPR and phi 3T the domains responsible for recognition of DNA methylation targets CCA/TGG, CCGG, GGCC (SPR) and GCNGC, GGCC (phi 3T) represent contiguous sequences of approximately 50 amino acids each. These domains are tandemly arranged and do not overlap. They are part of a 'variable' segment within the enzymes which is flanked by 'conserved' amino acids, which are very similar amongst bacterial monospecific and the multispecific Mtases studied here. These results follow from a mutational analysis of the SPR and phi 3T Mtase genes. They further support our concept of a modular enzyme organization, according to which variability of type II Mtases with respect to target recognition is achieved by a combination of the same enzyme core with a variety of target-recognizing domains.
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis; D001435:Bacteriophages / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D003429:Cross Reactions; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D008745:Methylation; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010957:Plasmids
chemical_list: D004279:DNA, Viral; D004248:DNA (Cytosine-5-)-Methyltransferases