MULTI-STEP MECHANISM OF CODON RECOGNITION BY tRNA: EVIDENCE OF CODON INDUCED tRNA DIMERIZATION D. LABUDA*, AND D. PÖRSCHKE

摘要: The joined fit of relaxation times and relaxation amplitudes ac. cording to the scheme/1/revealed the equilibrium constants of K-8 and K-1500 M-1, the association rate constants k= 1160 s and k-6.2 x106 M-1-1 and AH's of the order of 10 and 4 kcal/mole for step B and A, respectively, at 7.2 C. The fluorescence quantuum yields were obtained relative to the complex: 0.01 for form F and 1.28 for form H of tRNA. Thus, in conditions of buffer AB codon binds preferentially to highly fluorescent conformer/H/Phe of tRNA which predominates in solution. In the conditions of buffer ABT/0, 1 M Na and 10 mM Mgi 2+ in