Patent ID: 7604970

Claim:
A nucleic acid encoding a variant of the PapM polypeptide of bacteria of the Streptomyces genus comprising SEQ ID NO:2, selected from the group consisting of a polypeptide comprising the sequence of wild-type PapM polypeptide of S. pristinaespiralis modified by the replacement of residue Gly 249, a polypeptide comprising the sequence of wild-type PapM polypeptide of S. pristinaespiralis modified by the replacement of residue Thr 192, a polypeptide comprising the sequence of wild-type PapM polypeptide of S. pristinaespiralis modified by the replacement of residues Gly 249 and Thr 192, and wherein the variant of the PapM polypeptide catalyzes at least one of the methylation of PAPA to MMPAPA and the methylation of MMPAPA to DMPAPA and exhibits an efficiency of methylation, as defined by the ratio Kcat/Km, which differs from the efficiency of methylation of the wild-type PapM polypeptide of S. pristinaespiralis for at least one of the methylations of PAPA or MMPAPA.