tailieunhanh - Báo cáo khoa học: Interactions of elongation factor EF-P with the Escherichia coli ribosome

EF-P (eubacterial elongation factor P) is a highly conserved protein essen-tial for protein synthesis. We report that EF-P protects 16SrRNA near the G526 streptomycin and theS12 and mRNA binding sites (30ST-site). EF-P also protects domain V of the 23SrRNA proximal to the A-site (50ST-site) and more strongly the A-site of 70Sribosomes. | ỊFEBS Journal Interactions of elongation factor EF-P with the Escherichia coli ribosome Hiroyuki Aoki1 John Xu1 Andrew Emili2 John G. Chosay3 Ashkan Golshani4 and M. Clelia Ganoza1 1 University of Toronto . Best Institute Canada 2 Terrance Donnelly Centre for Cellular and Biomolecular Research Donnelly CCBR Toronto Canada 3 Pfizer Pharmaceuticals Ann Arbor MI USA 4 Department of Biology Carleton University Ottawa Canada Keywords A-site eIF5A elongation factor EF-P ribosomes translocation Correspondence H. Aoki University of Toronto . Best Institute 112 College Street Toronto Ontario M5G 1L6 Canada Fax 1 416 978 8528 Tel 1 416 978 8918 E-mail EF-P eubacterial elongation factor P is a highly conserved protein essential for protein synthesis. We report that EF-P protects 16S rRNA near the G526 streptomycin and the S12 and mRNA binding sites 30S T-site . EF-P also protects domain V of the 23S rRNA proximal to the A-site 50S T-site and more strongly the A-site of 70S ribosomes. We suggest that EF-P a may play a role in translational fidelity and b prevents entry of fMet-tRNA into the A-site enabling it to bind to the 50S P-site. We also report that EF-P promotes a ribosome-dependent accommodation of fMet-tRNA into the 70S P-site. Received 1 August 2007 revised 3 December 2007 accepted 10 December 2007 doi In all cells ribosomes are inert in the absence of several proteins that promote each facet of protein synthesis. In eubacteria initiation factors IF-1 IF-2 IF-3 bind to the 30S subunit whereas elongation factors EF-Tu and EF-G and termination factors RF-1 RF-2 and RF-3 bind to 70S ribosomes. Reconstitution of synthesis using all of these homogeneous proteins revealed that they are insufficient for synthesis directed by a native mRNA and that several other proteins are required 1-6 . One of these proteins EF-P stimulates peptide bond synthesis by 70S ribosomes 1 2 6-8 . The gene encoding EF-P efp occurs at