title: Proton coupling to [4Fe-4S](2+/+) and [4Fe-4Se](2+/+) oxidation and reduction in a designed protein.
abstract: The coupling of a single proton to [4Fe-4S]2+/+ oxidation/reduction in a de novo designed iron-sulfur protein maquette is presented. The reduced state pKared is 9.3, and the oxidized state pKaox is <6.5. The reduced state pKared shifts to 8.3 upon incorporation of a [4Fe-4Se]2+/+ cluster, implicating the cluster itself or its primary coordination sphere as the proton-coupling site.
authors.affiliation: Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Kennedy
authors.forename: Brian R
authors.initials: BR
authors.lastname: Gibney
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005288:Ferredoxins / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005288:Ferredoxins; D007506:Iron-Sulfur Proteins; D010446:Peptide Fragments