Creative Biolabs can provide the customers with highly affinity diphthamide-specific antibody discovery and production services based on the excellent High-Affi™ technology. These antibodies are produced by optimized immunization with a synthetic diphthamide modified peptide of EF-2 and purified by affinity chromatography. They do not cross-react with unmodified peptides.
Diphthamide is a unique post-translational modification of histidine amino acid found in eukaryotic and archaeal elongation factor 2 (EF-2) which enables the translocation of mRNA and peptidyl-tRNA from the A- to the P-site of the ribosome. Genetic and biochemical studies have revealed that diphthamide is evolutionally conserved among lower and higher eukaryotes.
The structure and biosynthetic pathway of diphthamide
The structure of diphthamide has been confirmed by X-ray crystallography, which is proposed to be a 2-[3-carboxyamido-3-(trimethylammonio)propyl]histidine. However, its stereochemistry is still uncertain.
The biosynthesis of diphthamide involves a multi-step pathway and is catalyzed by seven diphthamide biosynthesis proteins (DPH1-DPH7). There is a minimum of three steps to summarize the biosynthetic pathway.
Diphthamide modification proteins and sites
Further studies indicate that diphthamide exists only on EF2 and there is one diphthamide residue per EF2 protein within a highly conserved sequence. The modification sites have been determined in several species with His 715 in human, His 699 in yeast or the corresponding position in other species.
ADP-ribosylation reaction on the diphthamide residue
Diphthamide is named as it is the target of diphtheria toxin (DT) produced by Corynebacterium diphtheriae. Pseudomonas exotoxin A (PE) and DT enter cells and catalyze the ADP-ribosylation of diphthamide using nicotinamide adenine dinucleotide (NAD) as the ADP-ribosyl donor. This ADP-ribosylation modification of diphthamide inactivates eEF2, arrests protein synthesis, and leads to host cell death.
The biological function and related diseases of diphthamide
Recently, diphthamide has been reported for many important events and cause a series of diseases.
With years of developing and exploring, Creative Biolabs has established a broad platform for post-translational modification antibody discovery and production. Our Ph.D. level scientists will comprehensive evaluate the intention of customers and tailor the most suitable solution for them.
Fig. 1. The proposed biosynthetic pathway of diphthamide. (Su X, Lin Z, and Lin H 2013)
Creative Biolabs can provide a comprehensive list of PTM-specific antibody production services of your choice.