title: Analysis of HypD Disulfide Redox Chemistry via Optimization of Fourier Transformed ac Voltammetric Data.
abstract: Rapid disulfide bond formation and cleavage is an essential mechanism of life. Using large amplitude Fourier transformed alternating current voltammetry (FTacV) we have measured previously uncharacterized disulfide bond redox chemistry in Escherichia coli HypD. This protein is representative of a class of assembly proteins that play an essential role in the biosynthesis of the active site of [NiFe]-hydrogenases, a family of H2-activating enzymes. Compared to conventional electrochemical methods, the advantages of the FTacV technique are the high resolution of the faradaic signal in the higher order harmonics and the fact that a single electrochemical experiment contains all the data needed to estimate the (very fast) electron transfer rates (both rate constants ≥ 4000 s-1) and quantify the energetics of the cysteine disulfide redox-reaction (reversible potentials for both processes approximately -0.21 ± 0.01 V vs SHE at pH 6). Previously, deriving such data depended on an inefficient manual trial-and-error approach to simulation. As a highly advantageous alternative, we describe herein an automated multiparameter data optimization analysis strategy where the simulated and experimental faradaic current data are compared for both the real and imaginary components in each of the 4th to 12th harmonics after quantifying the charging current data using the time-domain response.
authors.affiliation: Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom.
authors.forename: Hope
authors.initials: H
authors.lastname: Adamson
authors.affiliation: Department of Computer Science, University of Oxford , Wolfson Building, Parks Road, Oxford, OX1 3QD, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Robinson
authors.affiliation: Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom.
authors.forename: Paul S
authors.identifier: 0000-0002-8465-4823
authors.initials: PS
authors.lastname: Bond
authors.affiliation: Experimental Molecular Biophysics, Freie Universität Berlin , Arnimalle 14, 14195 Berlin, Germany.
authors.forename: Basem
authors.initials: B
authors.lastname: Soboh
authors.affiliation: Mathematical Institute, Andrew Wiles Building, University of Oxford , Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, United Kingdom.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Gillow
authors.affiliation: School of Chemistry and the ARC Centre of Excellence for Electromaterials Science, Monash University , Clayton, Victoria 3800, Australia.
authors.forename: Alexandr N
authors.identifier: 0000-0003-3063-6539
authors.initials: AN
authors.lastname: Simonov
authors.affiliation: School of Engineering and Mathematical Sciences, La Trobe University , Bundoora, Victoria 3086, Australia.
authors.forename: Darrell M
authors.initials: DM
authors.lastname: Elton
authors.affiliation: School of Chemistry and the ARC Centre of Excellence for Electromaterials Science, Monash University , Clayton, Victoria 3800, Australia.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Bond
authors.affiliation: Institute for Biology/Microbiology, Martin Luther University Halle-Wittenberg , Halle (Saale), Germany.
authors.forename: R Gary
authors.initials: RG
authors.lastname: Sawers
authors.affiliation: Department of Computer Science, University of Oxford , Wolfson Building, Parks Road, Oxford, OX1 3QD, United Kingdom.
authors.forename: David J
authors.initials: DJ
authors.lastname: Gavaghan
authors.affiliation: Department of Chemistry, University of York , Heslington, York, YO10 5DD, United Kingdom.
authors.forename: Alison
authors.identifier: 0000-0003-4715-7200
authors.initials: A
authors.lastname: Parkin