Meta-Biol

• Pathways

The diphthamide biosynthesis protein 2 (DPH2) subunit of the cytosolic DPH1:DPH2:DPH3 complex catalyzes the transfer of a 3-amino-3-carboxypropyl group from S-adenosylmethionine (AdoMet) to residue 715 of nascent elongation factor 2 (EEF2), forming aminocarboxypropyl EEF2 and S-methylthioadenosine (MTAD). The association of DPH1, 2, and 3 to form a complex is inferred from studies of the homologous yeast proteins (Abdel-Fattah et al. 2013; Bar et al. 2008) and more limited studies of interactions among mouse and human ones (Liu et al. 2004). The identification of DPH2 as the catalytically active subunit of the DPH1:DPH2:DPH3 complex is inferred from the properties of the homologous Pyrococcus horikoshii protein (Zhang et al. 2010). DPH4 (DNAJC24) is needed for the reaction to occur but its exact role is unknown (Liu et al. 2004; Su et al. 2013). DPH3 is an electron donor for DPH1-DPH2 in the first step of diphthamide biosynthesis (Dong et al. 2014).