A mutation in codon 717 of the CHO-K1 elongation factor 2 gene prevents the first step in the biosynthesis of diphthamide.
The histidine residue at position 715 of elongation factor 2 (EF-2) is posttranslationally modified in a series of enzymatic reactions to 2-[3-carboxyamido-3-(trimethylammonio)-propyl]histidine, which has been given the trivial name diphthamide. The diphthamide residue of EF-2 is the target site for ADP ribosylation by diphtheria toxin and Pseudomonas exotoxin A. ADP-ribosylated EF-2 does not function in protein synthesis. EF-2 that has not been posttranslationally modified at histidine 715 is resistant to ADP ribosylation by these toxins. In this report we show that a G-to-A transition in the first position of codon 717 of the EF-2 gene results in substitution of arginine for glycine and prevents addition of the side chain of diphthamide to histidine 715 of EF-2. EF-2 produced by the mutant gene is fully functional in protein synthesis.
Department of Microbiology and Molecular Genetics, Markey Center for Molecular Genetics, University of Vermont, Burlington 05405.
B T
BT
Foley
J M
JM
Moehring
T J
TJ
Moehring
D000225:Adenine; D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine; D001483:Base Sequence; D016466:CHO Cells; D003062:Codon; D006224:Cricetinae; D005998:Glycine; D006147:Guanine; D006639:Histidine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism; D006720:Homozygote; D008969:Molecular Sequence Data; D009154:Mutation; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length
D003062:Codon; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D006639:Histidine; D006147:Guanine; C027527:diphthamide; D001120:Arginine; D000225:Adenine; D005998:Glycine