Abstract
Purified Phe-tRNAPhe revealed higher affinity to the donor (D) site of vacant 70S . poly(U) complex than to the acceptor (A) site, independent on Mg2+ concentration. As a result, in excess of ribosomes Phe-tRNAPhe binds exclusively to the D site. This was proved using the tests in the presence of tetracycline and puromycin. Preferential binding of Phe-tRNAPhe to the D site was used to measure equilibrium association constants of this interaction at different temperatures and Mg2+ concentrations. A large value of reaction enthalpy (ca. -26 Kcal/mole) was found.
MeSH terms
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Anticodon / genetics*
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Bacterial Proteins / metabolism
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Calorimetry
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Codon / genetics*
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Guanosine Triphosphate / metabolism
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Kinetics
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Magnesium / pharmacology
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Peptide Elongation Factor Tu
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Peptide Elongation Factors / metabolism
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RNA, Messenger / genetics*
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RNA, Transfer / genetics*
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RNA, Transfer, Amino Acyl / genetics*
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RNA, Transfer, Amino Acyl / metabolism
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Ribosomes / metabolism*
Substances
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Anticodon
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Bacterial Proteins
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Codon
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Peptide Elongation Factors
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RNA, Messenger
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RNA, Transfer, Amino Acyl
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Guanosine Triphosphate
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RNA, Transfer
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Peptide Elongation Factor Tu
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Magnesium