Cloning and characterization of the gene encoding M.FauI DNA methyltransferase

The enzymes of the FauI restriction-modification system from the Flavobacterium aquatile strain recognize the non-palindromic sequence 5'-CCCGC-3'/3'-GG-GCG-5'. We have cloned the gene encoding the DNA modifying component of this system and determined its nucleotide sequence. The deduced amino acid sequence contains ten conserved motifs characteristic for [cytosine-5] DNA methyltransferases. Part of the gene sequence that encodes the putative target recognizing domain of the M.FauI shows some homology with the downstream region, thus indicating that duplication of the DNA segment was probably involved in the gene evolution.