[The unique FauI restriction-modification system: cloning and comparative analysis of protein structure].

The nucleotide sequence was established for the full-length Flavobacterium aquatile operon coding for the FauI restriction-modification system. The operon is unusual in structure and has the gene order control protein gene-DNA methyltransferase A gene-restriction endonuclease gene-DNA methyltransferase B gene, other than in the known analogs. The genes are similarly oriented and overlap. On evidence of sequence analysis, both methyltransferases are C5 enzymes, the control protein is similar to that of other restriction-modification systems, and restriction endonuclease is low-homologous to other enzymes cleaving the DNA upper strand in position 4 or 5 relative to the recognition site.