title: Proton-coupled electron transfer: a unifying mechanism for biological charge transport, amino acid radical initiation and propagation, and bond making/breaking reactions of water and oxygen.
abstract: Redox-driven proton pumps, radical initiation and propagation in biology, and small-molecule activation processes all involve the coupling of electron transfer to proton transport. A mechanistic framework in which to interpret these processes is being developed by examining proton-coupled electron transfer (PCET) in model and natural systems. Specifically, PCET investigations are underway on the following three fronts: (1) the elucidation of the PCET reaction mechanism by time-resolved laser spectroscopy of electron donors and acceptors juxtaposed by a proton transfer interface; (2) the role of amino acid radicals in biological catalysis with the radical initiation and transport processes of E. coli ribonucleotide reductase (RNR) as a focal point; and (3) the application of PCET towards small-molecule activation with emphasis on biologically relevant bond-breaking and bond-making processes involving oxygen and water. A review of recent developments in each of these areas is discussed.
authors.affiliation: Department of Chemistry, 6-335, 77 Massachusetts Avenue, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Chang
authors.forename: Michelle C Y
authors.initials: MC
authors.lastname: Chang
authors.forename: Niels H
authors.initials: NH
authors.lastname: Damrauer
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Nocera
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D008954:Models, Biological; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010782:Photolysis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018892:Proton-Motive Force; D012264:Ribonucleotide Reductases / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D000596:Amino Acids; D005609:Free Radicals; D045332:Photosystem II Protein Complex; D014867:Water; D012264:Ribonucleotide Reductases; D003576:Electron Transport Complex IV; D010100:Oxygen