title: Amino acid sequence of mammalian elongation factor 2 deduced from the cDNA sequence: homology with GTP-binding proteins.
abstract: Complementary DNA clones, pHEW1 and pRE2, coding for hamster and rat polypeptide chain elongation factor 2 (EF-2), respectively, were isolated and sequenced. It was shown that the cDNA insert in pHEW1 contains a 2574-base-pair open reading frame coding for an 857-amino acid polypeptide with Mr 95,192, excluding the initiation methionine. Comparative studies of sequence homology among EF-2 and several GTP-binding proteins show that five regions in the amino-terminal position of EF-2, corresponding to about 160 amino acids, show homology with GTP-binding proteins, including protein synthesis elongation and initiation factors, mammalian ras proteins, and transducin. The carboxyl-terminal half of EF-2 contains several regions that have 34-75% homology with bacterial elongation factor G. These results suggest that the amino-terminal region of EF-2 participates in the GTP-binding and GTPase activity whereas the carboxyl-terminal region interacts with ribosomes. Finally, the sequence provides direct evidence that diphthamide (2-[3-carboxy-amido-3-(trimethylammonio)propyl]histidine), the site of ADP-ribosylation by diphtheria toxin, is produced by post-translational modification of a histidine residue in the primary translational product.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006224:Cricetinae; D004247:DNA / Q000032:analysis; D004262:DNA Restriction Enzymes; D020963:GTP Phosphohydrolase-Linked Elongation Factors / Q000032:analysis; D019204:GTP-Binding Proteins / Q000235:genetics*; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000235:genetics*; D051381:Rats; D012689:Sequence Homology, Nucleic Acid
chemical_list: D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D004247:DNA; D004262:DNA Restriction Enzymes; D020963:GTP Phosphohydrolase-Linked Elongation Factors; D019204:GTP-Binding Proteins