Diphthamide
Chemical compound
From Wikipedia, the free encyclopedia
Diphthamide is a post-translationally modified histidine amino acid found in archaeal and eukaryotic elongation factor 2 (eEF-2).
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| Names | |
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| IUPAC name
2-Amino-3-[2-(3-carbamoyl-3-trimethylammonio-propyl)-3H-imidazol-4-yl]propanoate | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C13H23N5O3 | |
| Molar mass | 297.354 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Dipthamide is named after the toxin produced by the bacterium Corynebacterium diphtheriae, which targets diphthamide.[1] Besides this toxin, it is also targeted by exotoxin A from Pseudomonas aeruginosa.[1][2] It is the only target of these toxins.[2]
Structure and biosynthesis
Diphthamide is proposed to be a 2-[3-carboxyamido-3-(trimethylammonio)propyl]histidine. Though this structure has been confirmed by X-ray crystallography, its stereochemistry is uncertain.[1][3]
Diphthamide is biosynthesized from histidine and S-adenosyl methionine (SAM).[1] The side chain bound to imidazole group and all methyl groups come from SAM. The whole synthesis takes place in three steps:[1]
- transfer of 3-amino-3-carboxypropyl group from SAM
- transfer of three methyl groups from SAM – synthesis of diphtine
- amidation – synthesis of diphthamide
In eukaryotes, this biosynthetic pathway contains a total of 7 genes (Dph1-7).[1]
Biological function
Diphthamide ensures translation fidelity.[1]
The presence or absence of diphthamide is known to affect NF-κB or death receptor pathways.[4]