The phosphate clamp as recognition motif in platinum–DNA interactions

Abstract

This review summarizes studies on substitution-inert polynuclear platinum complexes (PPCs) which bind to DNA through the phosphate clamp – a discrete mode of DNA–ligand recognition distinct from the canonical intercalation and minor-groove binding. Especially, this review concentrates on comparing the binding and conformational changes induced by trinuclear platinum complexes with dinuclear spermine-linked complexes. The protonated central polyamine –+NH2–(CH2)4–N+H2– of spermine allows direct comparison with the central Pt(tetraamine) moiety of the trinuclear complexes. The weight of the evidence suggests that while overall charge on the small molecule determines binding affinity, the presence of minor groove spanning from the phosphate clamp is important in conformational changes and in sequence selectivity.