title: Design of a single protein that spans the entire 2-V range of physiological redox potentials.
abstract: The reduction potential (E°') is a critical parameter in determining the efficiency of most biological and chemical reactions. Biology employs three classes of metalloproteins to cover the majority of the 2-V range of physiological E°'s. An ultimate test of our understanding of E°' is to find out the minimal number of proteins and their variants that can cover this entire range and the structural features responsible for the extreme E°'. We report herein the design of the protein azurin to cover a range from +970 mV to -954 mV vs. standard hydrogen electrode (SHE) by mutating only five residues and using two metal ions. Spectroscopic methods have revealed geometric parameters important for the high E°'. The knowledge gained and the resulting water-soluble redox agents with predictable E°'s, in the same scaffold with the same surface properties, will find wide applications in chemical, biochemical, biophysical, and biotechnological fields.
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
authors.forename: Parisa
authors.initials: P
authors.lastname: Hosseinzadeh
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Marshall
authors.affiliation: Institute of Environmental and Health, Division of Environmental and Biomolecular Systems, Oregon Health and Science University, Portland, OR 97239; Department of Chemistry, Reed College, Portland, OR 97202;
authors.forename: Kelly N
authors.identifier: http://orcid.org/0000-0003-1332-7283
authors.initials: KN
authors.lastname: Chacón
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nilges
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
authors.forename: Siu Yee
authors.initials: SY
authors.lastname: New
authors.affiliation: Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
authors.forename: Stoyan A
authors.initials: SA
authors.lastname: Tashkov
authors.affiliation: Institute of Environmental and Health, Division of Environmental and Biomolecular Systems, Oregon Health and Science University, Portland, OR 97239;
authors.forename: Ninian J
authors.initials: NJ
authors.lastname: Blackburn
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801; yi-lu@illinois.edu.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lu
mesh_terms: D001400:Azurin / Q000737:chemistry / Q000378:metabolism*; D055664:Electrochemical Techniques; D004578:Electron Spin Resonance Spectroscopy; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D010084:Oxidation-Reduction; D015202:Protein Engineering; D013052:Spectrometry, X-Ray Emission; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001400:Azurin
keywords: azurin; cupredoxins; electron transfer; reduction potential; secondary coordination sphere