No abstract

No abstract

A new series of pyridine-containing analogues III-XXII of distamycin A and netrop sin was investigated by the molecular mechanics technique and molecular modelling. A pyridine analogue of netropsin (VII) is described, the first compound based on molecular studies, and two carbocyclic analogues of distamycin A with an N-terminal chloro- or bromoacetyl group (VIa, VIIa) were synthesized, as well as carbocyclic analogues of netropsin (VIIIb, Xb), potential carriers of alkylating elements. The potential use of VIa, VII, VIIa, VIIIb and Xb as carriers to place into the minor groove of DNA chemical groups capable of modifying DNA, is discussed.

Key words: DNA-ligand interaction, carbocyclic analogues of netropsin and distamycin, molecular modelling, netropsin, distamycin A molecular mechanics and molecular dynamics approach was used to examine the structure of complexes formed between the d(CGCGAATTCGCG) 2 duplex and netropsin, distamycin, and four carbocyclic analogues of netropsin and distamycin (1-4). The resulting structures of the ligand-DNA model complexes and their energetics were examined. It is predicted that the compounds 1-4 should have a decreased affinity for the minor groove of AT-rich regions in comparison to netropsin and distamycin. From the energetic analysis it appears that van der Waals and electrostatic interactions are more important than specific hydrogen bonds in stabilizing the ligand-duplex complexes. We predict that compounds 1 and 2 are effectively isohelical with the DNA minor groove. The superior DNA-binding afforded by 1 and 2 in comparison to 3 and 4 results from their more effective penetration into the minor groove and smaller perturbation of molecular structure upon complex formation.A, compounds 1 (R = H) and 2 (R = OCH 3 ); B, compounds 3 (R = H) and 4 (R = OCH 3 ).

No abstract