This amidase catalyses the last step in the conversion of an L-histidine residue in the translation elongation factor EF2 to diphthamide. This factor is found in all archaea and eukaryota, but not in eubacteria, and is the target of bacterial toxins such as the diphtheria toxin and the Pseudomonas exotoxin A (see EC 2.4.2.36, NAD+---diphthamide ADP-ribosyltransferase). The substrate of the enzyme, diphthine, is produced by EC 2.1.1.98, diphthine synthase.
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The expected taxonomic range for this enzyme is: Eukaryota, Archaea, Bacteria
This amidase catalyses the last step in the conversion of an L-histidine residue in the translation elongation factor EF2 to diphthamide. This factor is found in all archaea and eukaryota, but not in eubacteria, and is the target of bacterial toxins such as the diphtheria toxin and the Pseudomonas exotoxin A (see EC 2.4.2.36, NAD+---diphthamide ADP-ribosyltransferase). The substrate of the enzyme, diphthine, is produced by EC 2.1.1.98, diphthine synthase.
the repurified DELTAdph7 eEF-2 is a substrate for the amidation by Dph6 alone. In contrast, FLAG-tagged DELTAdph7 eEF-2 incubated without Dph7 does not form diphthamide
the repurified DELTAdph7 eEF-2 is a substrate for the amidation by Dph6 alone. In contrast, FLAG-tagged DELTAdph7 eEF-2 incubated without Dph7 does not form diphthamide
Dph7, i.e. YBR246w, apparently couples diphthine synthase to diphthine amidation. Dph6 and Dph7 are components required for the amidation step of the diphthamide pathway. In contrast to Dph6, Dph7 may be regulatory. DPH6 and DPH7 are novel sordarin effectors, a feature they share with the diphthamide synthesis genes DPH1-DPH5
failure to synthesize diphthamide affects the accuracy of protein synthesis, DPH6 and DPH7 deletions cause phenotypes typical of bona fide diphthamide mutants, diphthine accumulation in dph6 and dph7 mutants, overview
a dph6 deletion strain specifically accumulates the diphthine-modified form of EF2, and shows a failure to complete diphthine amidation resulting in loss of ADP ribosylation acceptor activity of EF2 in the presence of diphtheria toxin in vitro. The amidation defect partially protects against DT in vivo and correlates with resistance to EF2 inactivation and growth inhibition by sordarin, collectively traits typical of bona fide diphthamide synthesis mutants
a dph6 deletion strain specifically accumulates the diphthine-modified form of EF2, and shows a failure to complete diphthine amidation resulting in loss of ADP ribosylation acceptor activity of EF2 in the presence of diphtheria toxin in vitro. The amidation defect partially protects against DT in vivo and correlates with resistance to EF2 inactivation and growth inhibition by sordarin, collectively traits typical of bona fide diphthamide synthesis mutants
diphthamide is formed on eEF-2 only in the presence of both Dph6 and Dph7 enzymes. Enzyme DPH6 catalyzes the last step in the diphthamide synthesis pathway, the amidation of diphthine bound to translation elongation factor 2, while enzyme DPH7 is a methylesterase converting methylated diphthine to diphthine, so that Dph6 can convert it to diphthamide. Diphthamide synthesis pathway, overview
diphthamide is formed on eEF-2 only in the presence of both Dph6 and Dph7 enzymes. Enzyme DPH6 catalyzes the last step in the diphthamide synthesis pathway, the amidation of diphthine bound to translation elongation factor 2, while enzyme DPH7 is a methylesterase converting methylated diphthine to diphthine, so that Dph6 can convert it to diphthamide. Diphthamide synthesis pathway, overview
the enzyme, encoded by gene dph6, catalyzes the biosynthesis of diphthamide, which is a highly modified histidine residue in eukaryal translation elongation factor 2 that is the target for irreversible ADP-ribosylation by diphtheria toxin
Dph6 is an ATP-dependent diphthamide synthetase that catalyses the reaction using ammonium as a cofactor. Diphthamide is a highly conserved modification of archaeal and eukaryal translation elongation factor 2. Dph6 is the catalytically relevant amidase in the amidation step of diphthamide synthesis
Dph6 is an ATP-dependent diphthamide synthetase that catalyses the reaction using ammonium as a cofactor. Diphthamide is a highly conserved modification of archaeal and eukaryal translation elongation factor 2. Dph6 is the catalytically relevant amidase in the amidation step of diphthamide synthesis
6.3.1.14 diphthine-ammonia ligase
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