InterPro domain: IPR019257

The mycobacterial members of this family are expressed from part of the ergothioneine biosynthetic gene cluster. EGTD is the histidine methyltransferase that transfers three methyl groups to the alpha-amino moiety of histidine, in the first stage of the production of this histidine betaine derivative that carries a thiol group attached to the C2 atom of an imidazole ring [ 1 ].

1. In vitro reconstitution of Mycobacterial ergothioneine biosynthesis. J. Am. Chem. Soc. 132, 6632-3