Poster abstracts

Poster number 19 submitted by Corinne Hausmann

An aminoacyl-tRNA synthetase:elongation factor complex for substrate channeling in archaeal translation

Corinne D. Hausmann (Department of Microbiology, The Ohio State University), Mette Praetorius-Ibba (Department of Radiology, The Ohio State University), Michael Ibba (Department of Microbiology, The Ohio State University)

Abstract:
Translation requires the specific attachment of amino acids to tRNAs by aminoacyl-tRNA synthetases (aaRSs) and the subsequent delivery of aminoacyl-tRNAs to the ribosome by elongation factor 1 alpha (EF-1a). Interactions between EF-1a and various aaRSs have been described in eukaryotes, but the role of these complexes remains unclear. To investigate possible interactions between EF-1a and other cellular components, a yeast two-hybrid screen was performed for the archaeon Methanothermobacter thermautotrophicus. EF-1a was found to form a stable complex with leucyl-tRNA synthetase (LeuRS; Kd = 0.7 uM). Complex formation had little effect on EF-1a activity, but increased the rate of Leu-tRNALeu synthesis 8-fold. In addition, EF-1a co-purified with the archaeal multi-synthetase complex (MSC) comprised of LeuRS, LysRS and ProRS, suggesting the existence of a larger aaRS:EF-1a complex in archaea. These interactions between EF-1a and the archaeal MSC may promote the efficiency of translation both by enhancing the aminoacylation efficiencies of the three associated aaRSs and by coupling two stages of translation: aminoacylation of cognate tRNAs and their subsequent channeling to the ribosome.

References:
Hausmann, C.D., Praetorius-Ibba, M., and Ibba, M. (2007) Nucl. Acids Res. In press.

Praetorius-Ibba, M., Hausmann, C.D., Paras, M., Rogers, T.E., and Ibba, M. (2007) J. Biol. Chem., 282, 3680-3687.

Keywords: Elongation factor 1 alpha; EF-1a, Aminoacyl-tRNA synthetase; aaRS