A conserved amino acid sequence around Arg-68 of Artemia elongation factor 1 alpha is involved in the binding of guanine nucleotides and aminoacyl transfer RNAs.

The rate of trypsin cleavage of elongation factor 1 alpha having bound GDP is low and increases on exchange of GDP for GTP. The cleavage occurs at a unique position of the protein chain, namely at arginine-68 of Artemia EF-1 alpha. This increase in trypsin sensitivity is enhanced further in the presence of charged or uncharged transfer RNA. The local unfolding of EF-alpha at residue 68 is discussed in terms of a model in which GTP hydrolysis controls the positioning of a short 3'-terminal section of transfer RNA near the centre of peptide bond synthesis.