Location of multiple binding sites for testo and testo-Pt(II) with tRNA

摘要

We report the binding of testo and testo-Pt(II) complexes (testosterone derivatives) with tRNA in aqueous solution at physiological pH. Thermodynamic parameter Delta H-0 -8 to -3 (kJ mol(-1)), Delta S-0 35 to 18 (J mol(-1)K(-1)) and Delta G(0) -14 to -13 (kJ mol(-1)) and other spectroscopic results showed drug-tRNA binding occurs via ionic contacts with testo-Pt(II) forming more stable tRNA complexes in comparison to testo: K-testo-Pt(II)-tRNA= 3.2 (+/- 0.9) x 10(5) M-1 > K-testo-tRNA= 2.1 (+/- 0.7) x 10(5) M-1. Molecular modeling showed multiple binding sites for testo and testo-Pt(II) on tRNA molecule. Some of the useful molecular descriptors are calculated. Major structural changes were observed for biopolymers upon drug complexation, while tRNA remains in the A-family structures.