Increase of fidelity of polypeptide synthesis by spermidine in eukaryotic cell-free systems.
The mechanism of spermidine-induced increase of fidelity of polypeptide synthesis in a wheat germ cell-free system has been studied. It was found that the increase of fidelity in the presence of spermidine occurred mainly at the level of binding of aminoacyl-tRNA to ribosomes, that reduction of misreading was more marked at the 5'-base than at the 3'-base of the codon and that misreading caused by paromomycin and kanamycin C was not significantly decreased by spermidine. It was deduced from these results that spermidine inhibited low-frequency misreading more strongly than high-frequency misreading. In addition, spermidine was found to stimulate the rejection of non-cognate aminoacyl-tRNA mainly at an initial discrimination step during the binding of amino-acyl-tRNA to ribosomes, and slightly at a subsequent GTP-dependent discrimination step, the so-called proofreading step. In yeast, rabbit reticulocyte, and Artemia salina cell-free systems, spermidine was found to increase the fidelity of protein synthesis.
D000818:Animals; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D010445:Peptide Elongation Factors / Q000378:metabolism; D010455:Peptides / Q000235:genetics; D010944:Plants / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000187:drug effects*; D012343:RNA, Transfer / Q000235:genetics; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics; D051381:Rats; D012270:Ribosomes / Q000378:metabolism*; D013095:Spermidine / Q000494:pharmacology*; D014908:Triticum / Q000378:metabolism
D010445:Peptide Elongation Factors; D010455:Peptides; D012346:RNA, Transfer, Amino Acyl; D012343:RNA, Transfer; D008274:Magnesium; D013095:Spermidine