title: Metal ion modulated electron transfer in photosynthetic proteins.
abstract: 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.
authors.affiliation: Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Utschig
authors.forename: Marion C
authors.initials: MC
authors.lastname: Thurnauer
mesh_terms: D001665:Binding Sites; D003300:Copper / Q000737:chemistry; D004579:Electron Transport; D004583:Electrons; D007501:Iron / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D011487:Protein Conformation; D018717:Purple Membrane / Q000737:chemistry; D012242:Rhodobacter sphaeroides / Q000737:chemistry; D013696:Temperature; D015032:Zinc / Q000737:chemistry
chemical_list: D008670:Metals; D045322:Photosynthetic Reaction Center Complex Proteins; D003300:Copper; D007501:Iron; D015032:Zinc