Metal ion modulated electron transfer in photosynthetic proteins.

Accounts of chemical research

PubMedID: 15260506

Utschig LM, Thurnauer MC. Metal ion modulated electron transfer in photosynthetic proteins. Acc Chem Res. 2004;37(7):439-47.
Photosynthetic purple bacterial reaction center (RC) proteins are ideal native systems for addressing basic questions regarding the nature of biological electron transfer because both the protein structure and the electron-transfer reactions are well-characterized. Metal ion binding to the RC can affect primary photochemistry and provides a probe for understanding the involvement of local protein environments in electron transfer. The RC has two distinct transition metal ion binding sites, the well-known non-heme Fe(2+) site buried in the protein interior and a recently discovered Zn(2+) site located on the surface of the protein. Fe(2+) removal and Zn(2+) binding systematically affect different electron-transfer steps in the RC. Factors involved in the metal ion alteration of RC electron transfer may provide a paradigm for other biological systems involved in electron transfer.