Phosphate recognition by sapphyrin. A new approach to DNA binding

Molecular recognition of DNA is one of the most important processes in nature, and the interactions of small molecules with DNA continues to be an area of active interest. In broad terms, three main types of noncovalent small molecule-DNA interactions have been described: intercalation, groove binding, and simple electrostatic attraction. In this paper we present a new type of small molecule-DNA interaction in which the monoprotonated form of sapphyrin 2, a non-naturally occurring aromatic pentapyrollic macrocycle, "chelates" the anionic phosphate backbone of DNA in a precise, rigid fashion.