The role of guanine nucleotides in the interaction between aminoacyl-tRNA and elongation factor 1 of Artemia salina.

The low-molecular-weight form of elongation factor 1 (EF-1L) of the cysts of the brine shrimp Artemia salina and [3H]phenylalanyl-tRNA are able to form a stable complex which can be isolated on a Sephacryl S200 column. The formation of this complex is inhibited by increasing concentrations of magnesium acetate and KCl. Furthermore, the formation of this complex is independent of the presence of guanine nucleotides. Complex formation between EF-1L and phenylalanyl-tRNA appears to be specific, since acylation of the tRNA is a necessity for this interaction. Although EF-1L alone binds GDP somewhat more strongly than GTP, the complex between EF-1L and phenylalanyl-tRNA binds GTP exclusively. Our results support the idea that complex formation between EF-1L and aminoacyl-tRNA precedes the enzymatic binding of aminoacyl-tRNA to the 80-S ribosome. Subsequently to this binding, release of EF-1L from the ribosome occurs.