Stoichiometry of GTP hydrolysis in a poly(U)-dependent cell-free translation system. Determination of GTP/peptide bond ratios during codon-specific elongation and misreading.
The stoichiometry of GTP hydrolysis during peptide elongation in the processes of codon-specific translation and misreading of polyuridylic acid was determined in a cell-free system in which all ribosomes were active in peptide synthesis. Ribosomes carrying oligophenylalanine presynthesized on poly(U) covalently bound to Sepharose were used. In the codon-specific translation of poly(Phe) on poly(U)-Sepharose at optimal Mg2+ concentration (6 mM MgCl2), the ratio of GTP cleaved to Phe polymerized was found to be about 2 (+/- 0.1). Under the same conditions but during misreading (elongation of polyleucine on poly(U)-Sepharose) the GTP/Leu ratio increased 10 times (from 16 to 25 in different experiments).
D003062:Codon; D004926:Escherichia coli / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D010452:Peptide Biosynthesis; D010441:Peptide Chain Elongation, Translational; D010455:Peptides; D011072:Poly U; D014176:Protein Biosynthesis; D012270:Ribosomes / Q000378:metabolism*
D003062:Codon; D010455:Peptides; C027819:polyleucine; D011072:Poly U; C012001:polyphenylalanine; D006160:Guanosine Triphosphate