Nucleotide Sequence of Fortimicin KL1 Methyltransferase Gene Isolated from Micromonosporaolivasterospora, and Comparison of Its Deduced Amino Acid Sequence with Those of Methyltransferases Involved in the Biosynthesis of Bialaphos and Fosfomycin

catalyzed by PnAAmethyltransferase. Based on the finding that fosfomycin non-producing mutants defective in the biosynthesis of vitamin B12 incorporated [methyl14C]methylcobalamin to fosfomycin, we proposed that PnAAwas directly methylated by a nucleophilic attack of the methyl anion derived from methylcobalamin catalyzed by PnAAmethyltransferase5). More recently we have determined the nucleotide sequences of the genes encoding P-methyltransferase6)