The ligand-structure-selective binding of oligonucleotide by cobalt complexes

摘要

The binding of two Co(III) complexes [Co(phen)2(DPQ)]~(3+) and [Co(phen)2(HPlP)]Cl3 [HPIP = 2-(2-hydroxy-phenyl) imidazo [4,5-f)[1,10] phenanthroline, DPQ= dipyrido[3,2-f:2',3'-h]quinoxaline] to the normal base-paired decanucleotide d(CCTAATTAGG)2 was studied by 2D NMR. The results indicate that the width of intercalating ligand has a large effect on the selectivity of binding site. For [Co(phen)2(HPIP)]Cl3, the complex binds the decanucleotide at C2T3:G9A8 and A4A5:T7T6 by intercalation from the minor groove, while [Co(phen)2(DPQ)]~(3+) intercalates into T3A4:T7A8 region from the minor groove. The conclusion was further proved by molecular modeling.