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The disassembly of post‐termination complex (PoTC) by ribosome recycling factor (RRF) and EF‐G occurs first with the releases of tRNA, mRNA, and splitting of the ribosome in its order ‐‐ IF3 does not participate in this reaction
Author(s) -
Kaji Akira,
Iwakura Nobuhiro,
Kaji Hideko
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.986.1
Subject(s) - ribosome , transfer rna , messenger rna , protein biosynthesis , p site , rna , elongation factor , eukaryotic ribosome , initiation factor , ribosomal rna , translation (biology) , chemistry , ef tu , 30s , biophysics , biology , biochemistry , gene
Protein synthesis consists of four steps, initiation, elongation, termination, and ribosome recycling. The last step consists of three reactions; 1) tRNA release, 2) mRNA release from the PoTC, and 3) splitting of ribosomes into subunits. In E. coli , all three reactions are catalyzed by RRF and EF‐G/GTP. It has been suggested that IF3 participates in the splitting of ribosomes of PoTC (NAR 33 , 5591–5601, 2005). Splitting has been measured with fluorescent labeled ribosomal subunits (Mol Cell 18 , 403–412, 2005) which can detect the conformational change of ribosomes without splitting. The split subunits rapidly re‐associate. To prevent this, IF3 was added (RNA 11 , 1317–1328, 2005). In other cases external 50S subunits were added and the split subunits (labeled) were observed as 70S ribosomes (Mol Cell 18 , 675–686, 2005). These are indirect methods to measure splitting of ribosomes. In this paper, we haracterized PoTC as having one tRNA (P/E site) and mRNA. We further show direct evidence of splitting of PoTC without addition of IF3 by conducting the experiment in 4 mM Mg ++ . Using this system, kinetic analysis and measurement of subunits formation from the PoTC are consistent with the hypothesis that the release of tRNA takes place first followed by the mRNA release and the splitting of 70S ribosomes in this order. IF3 does not participate in any of these reactions. This research was supported by CBRI.