Diphthamide is a post-translationally modified histidine residue present in elongation factor 2, and is the target of diphtheria toxin. This gene encodes a protein that contains a WD-40 domain, and is thought to be involved in diphthamide biosynthesis. A similar protein in yeast functions as a methylesterase, converting methylated diphthine to diphthine, which can then undergo amidation to produce diphthamide. [provided by RefSeq, Oct 2016].