Elongation factor 1 beta gamma from Artemia. Purification and properties of its subunits.

Abstract

The guanine nucleotide exchange factor, elongation factor 1 beta gamma (EF-1 beta gamma) has been purified from Artemia cysts using an improved method. The protein consists of two distinct polypeptides with relative molecular masses of 26,000 (EF-1 beta) and 46,000 (EF-1 gamma). A nucleoside diphosphate phosphotransferase activity often found in EF-1 beta gamma preparations has been completely separated from the actual guanine nucleotide exchange stimulatory activity of EF-1 beta gamma, thus indicating that nucleotide diphosphate phosphotransferase is not an intrinsic property of EF-1 beta. Both EF-1 beta gamma and EF-1 beta have been shown to stimulate the following three reactions to a comparable degree: (a) exchange of GDP bound to EF-1 alpha with exogenous GDP; (b) EF-1 alpha-dependent binding of Phe-tRNA to ribosomes; (c) poly(U)-dependent poly(phenylalanine) synthesis. However, a significantly higher nucleotide exchange rate was observed in the presence of EF-1 beta gamma compared to EF-1 beta alone. Concerning elongation factor 1 gamma (EF-1 gamma) the following observations were made. In contrast to EF-1 beta, pure EF-1 gamma is rather insoluble in aqueous buffers, but the tendency to precipitate can be partially suppressed by the addition of detergents. In particular, EF-1 gamma partitions solely into the detergent phase of Triton X-114 solutions. EF-1 gamma is also more susceptible to spontaneous, specific fragmentation. It is remarkably that about 5% of the cellular pool of EF-1 beta gamma was found to be present in membrane fractions, under conditions where no EF-1 alpha was detectable in these fractions. Furthermore it was noted that EF-1 beta gamma copurified strongly with tubulin on DEAE-cellulose. Moreover, it was observed that from a mixture of EF-1 beta gamma and tubulin, EF-1 gamma coprecipitates with tubulin using a non-denaturating immunoprecipitation technique. These findings suggest that EF-1 gamma has a hydrophobic domain and interacts with membrane and cytoskeleton structures in the cell.

• Authors: G M Janssen, W Möller
• Journal: European journal of biochemistry (Eur J Biochem) Vol. 171 Issue 1-2 Pg. 119-29 (Jan 15 1988) ISSN: 0014-2956 [Print] England
• PMID: 3276514 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Detergents
• Macromolecular Substances
• Nucleotides
• Peptide Elongation Factors
• Tubulin

Topics

• Animals
• Artemia (physiology)
• Detergents
• Immunologic Techniques
• Macromolecular Substances
• Membranes (metabolism)
• Nucleotides (metabolism)
• Peptide Chain Elongation, Translational
• Peptide Elongation Factors (isolation & purification, metabolism)
• Protein Binding
• Solubility
• Tubulin (metabolism)