InterPro domain: IPR004551

Diphthine synthase ( 2.1.1.98 ), also known as diphthamide biosynthesis S-adenosylmethionine-dependent methyltransferase, participates in the modification of a specific histidine residue in elongation factor 2 (EF-2) of eukaryotes and archaea to diphthamide. It is required for the methylation step in dipthamide biosynthesis.

This entry also includes diphthine methyl ester synthase ( 2.1.1.314 ) from Saccharomyces cerevisiae (a product of the DPH5 gene), which is an S-adenosyl-L-methionine-dependent methyltransferase that catalyzes methylations of a modified histidine residue in translation elongation factor 2 (EF-2), to form an intermediate called diphthine methyl ester: the second step of diphthamide biosynthesis [ 1 ].

1. Dph7 catalyzes a previously unknown demethylation step in diphthamide biosynthesis. J. Am. Chem. Soc. 136, 6179-82