?
diphthamide biosynthesis enzyme Dph1/Dph2 domain Archaea and Eukaryotes, but not Eubacteria, share the property of having a covalently modified residue, 2'-[3-carboxamido-3-(trimethylammonio)propyl]histidine, as a part of a cytosolic protein. The modified His, termed diphthamide, is part of translation elongation factor EF-2 and is the site for ADP-ribosylation by diphtheria toxin. This model includes both Dph1 and Dph2 from Saccharomyces cerevisiae, although only Dph2 is found in the Archaea (see TIGR03682). Dph2 has been shown to act analogously to the radical SAM (rSAM) family (pfam04055), with 4Fe-4S-assisted cleavage of S-adenosylmethionine to create a free radical, but a different organic radical than in rSAM. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",