Carbocyclic analogues of lexitropsin--DNA affinity and endonuclease inhibition.

A DNA-binding affinity and the effect on restriction enzymes activity of seven carbocyclic mono- and bis-lexitropsins and two analogues of pentamidine with unsubstituted N-terminal amine group were investigated. DNA association constants (Kapp) show that DNA affinity of mono-compounds is much weaker than netropsin and distamycin. Bis-analogues of netropsin bind DNA more strongly than mono-ligands, but without sequence-selectivity. Only pentamidine derivatives reveal preference to AT-rich sequence. The studied compounds can inhibit catalytical action of endonucleases recognizing sequence of four AT base pairs following one another.