The novel development on the binding affinities of self-assembled metal porphyrins to heterocycles, DNA base pairs and RNA has been introduced. Theoretical research in our group on the complexes formed by the metal porphyrins with heterocyclic and pharmaceutical molecules has been summarized. The metal porphyrins widely exist in the natural world and biological organisms. These binding processes are important to exploring and simulating the interactions among different kinds of cells in living things. The binding affinities of the self-assembled metal porphyrins to heterocycles are caused by ligation effects, hy-drogen bonds and π-π interactions. There exist four binding situations between the metal porphyrins and DNA. The binding processes of metal porphyrins to DNA and RNA result from hydrophobic, static and self-stacking interactions. The binding sites of cationic porphyrins to DNA are affected by the steric effect of substituents on the side chain. The metal porphyrins bind pharmaceutical molecules mainly via ligation in-teraction and hydrogen bonding. The complexes formed by ligation exhibit stronger binding affinities than those formed by hydrogen bonds.

Key words: metal porphyrin, heterocycle, DNA, pharmaceutical molecule, binding affinity