Cloning and expression of bombyx mori silk gland elongation factor 1γ in escherichia coli

Abstract

Elongation factor 1 (EF-1) from the silk gland of Bombyx mori consists of α-, β-, γ-, and δ-subunits. EF-1α•GTP catalyzes the binding of aminoacyl-tRNA to ribosomes concomitant with the hydrolysis of GTP. EF-1βγδ catalyzes the exchange of EF-1α-bound GDP for exogenous GTP and stimulates the EF-1α-dependent binding of aminoacyl-tRNA to ribosomes. EF-1γ cDNA, which contains an open reading frame (ORF) encoding a polypeptide of 423 amino acid residues, was amplified and cloned by PCR from a silk gland cDNA library. The calculated molecular mass and predicted pI of the product were 48,388 Da and 5.84, respectively. The silk gland EF-1γ shares 67.3% amino acid identity with Artemia salina EF-1γ. The N-terminal domain (amino acid residues 1–211) of silk gland EF-1γ is 29.3% identical to maize glutathione S-transferase. We demonstrated that silk gland EF-1γ bound to glutathione Sepharose, suggesting that the N-terminal domain of EF-1γ may have the capacity to bind to glutathione. © 2002 by Japan Society for Bioscience, Biotechnology, and Agrochemistry.