Binding Mechanism of meso-Tetrakis(4-) Porphyrin TMPyP4 with the Single-Strand DNA 5’-TTAGGG-3’ (1.School of Life Science, Beijing Institute of Technology, Beijing 100081, China; 2. School of Material Science and Engineering, Beijing Institute of

The binding mechanism of meso-tetrakis(4-(N-methylpyridiumyl))porphyrin (TMPyP4) and the telomeric sequence DNA 5'-TTAGGG-3' (S6) has been explored by means of circular dichroism spectrum, steady-state absorption, steady-state fluorescence and picosecond time-resolved fluorescence spectrums. DNA adopts the single-strand conformation in Tris-HCl buffer without any metal ions. The binding constant and the saturated binding number between TMPyP4 and S6 DNA were determined as 1.51×10⁶ (mol/L)^-1 and 1.2, respectively, according to steady-state absorption spectroscopy. Furthermore, on the findings of time-resolved fluorescence spectroscopic technique, the binding modes can be presumed.