摘要:
The preparation and DNA binding properties of ACDPI(n) (4-7, n = 1-4) and TACDPI(n) (8-10, n = 1-3) are detailed. Comparable to observations made with CDPI(n) (n = 1-5), ACDPI3 proved to be the optimal minor groove binding agent within the ACDPI(n) series, and the agents exhibited a selectivity for AT- versus GC-rich DNA which is most pronounced with ACDPI3. Similarly, TACDPI(n) (n = 1-3) exhibited a substantial AT- versus GC-rich DNA binding selectivity (n = 3, DELTA-DELTA-G-degrees = -2.7 to -3.5 kcal). The direct comparison of CDPI(n) with ACDPI(n) illustrated that the introduction of a C-5 amino substituent onto the peripheral face of the agent reduces the DNA binding affinity presumably through introduction of destabilizing electrostatic interactions. In contrast, the comparison with TACDPI(n) revealed that the introduction of a C-5 quaternary amine substantially enhanced the DNA binding affinity through introduction of stabilizing electrostatic interactions.