Interaction of synthetic analogs of distamycin with DNA. Role of the conjugated N-methylpyrrole system in specificity of binding.

Interaction of two synthetic analogs of distamycin (Dst), PPA and PAP, containing a saturated beta-alanine moiety replacing one N-methylpyrrole ring, with different polynucleotides and natural DNAs were studied using UV and CD spectroscopy. The results indicate that, similar to Dst, these analogs bind to DNA via the minor groove with a specificity towards AT-base pairs. It may be proposed that pyrrole chromophores in Dst probably do not play a role in the AT-base selectivity exhibited by Dst.