Chapter Eleven The methyltransferase gene superfamily: A tree with multiple branches

Abstract

This chapter reviews the most common S -adenosyl- l -methionine (AdoMet)-dependent methyl transferases (MTs) that have been cloned in various organisms, describes the structural–functional relationships of their genes, and traces the evolution of this gene superfamily. The most interesting prospects are the characterization of other genes encoding novel methyl transfer reactions, not only to increase the pool of genes for manipulation of plant secondary metabolism but also to contribute to a better understanding of the phylogenetic relationships of these genes. The brief inventory of the genes encoding the most common methyl transfer reactions indicates the ubiquity and universality of these essential enzymes among all organisms. The fact that the genes encoding MTs exhibit divergent sequences, both among themselves and among members of the same family, suggests that they have evolved from unrelated ancestral genes.