Mutual influence between contiguous TMPyP4 ligands when bound to a synthetic double-stranded Poly(A)-Poly(U)

作者：Tolstykh G; Kudrev A^*

来源：Journal of Molecular Structure, 2015, 1098: 342-350.

DOI：10.1016/j.molstruc.2015.06.031

• Binding
• Cooperativity
• TMPyP4
• Poly(A)-Poly(U)

The cooperativity of TMPyP4 ligand binding to Poly(A)-Poly(U) polynucleotide were monitored in this study by fluorescence spectroscopy and UV-Vis absorbance spectroscopy. To solve the equilibrium binding model between a dye and substrate, a new computational approach has been proposed based collectively on Principal Component Analysis and the conditional probabilities method. This approach suggest that the absorbance and fluorescence variance during a titration is determined by spectral species formed in stepwise saturation of binding sites on Poly(A)-Poly(U) with porphyrin and a conformational changes on a macromolecule. Spectral species assigned to different forms of polymer-ligand complexes whose existences in equilibrium were postulated by the conditional probabilities method. The binding of TMPyP4 molecule to the Poly(A)-Poly(U) enhances the binding of additional molecules to that same receptor. The intrinsic binding constant to an isolated binding site lgK(in) = 6.4, the cooperativity parameter omega = 5.0, and number of monomers occupied by a ligand n = 2 (25 degrees C; pH 7) were calculated based upon the non-linear least-squares fitting procedure.

• 出版日期2015-10-15