title: Site-directed mutagenesis of the highly perturbed copper site of auracyanin D.
abstract: Type-1 copper proteins participate in redox reactions and biological catalysis. Significant variation exists within the electronic structure of type-1 copper sites, producing both blue and green proteins. Classical, "blue" sites have been extensively studied, but "green" sites have been poorly characterized. We recently discovered a green copper protein, called auracyanin D. Here, we report a series of axial ligand mutations in auracyanin D, and characterize the resulting spectral and redox changes. The resulting mutants appear blue, green, and red and vary in redox potential from +56mV to +786mV. This is the largest change in redox potential to date for any type-1 center. We found that in this green protein, modifications of the axial ligand produce significantly larger changes than similar mutations in blue type-1 copper sites.
authors.affiliation: Graduate Program in Plant Biology, Washington University in St. Louis, St. Louis, MO 63130, United States.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: King
authors.affiliation: Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States.
authors.forename: Lucas
authors.initials: L
authors.lastname: Harrington
authors.affiliation: Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, United States.
authors.forename: Bryan M
authors.initials: BM
authors.lastname: Lada
authors.affiliation: Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States.
authors.forename: Guannan
authors.initials: G
authors.lastname: He
authors.affiliation: Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, United States.
authors.forename: Jason W
authors.initials: JW
authors.lastname: Cooley
authors.affiliation: Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States; Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center (PARC), Washington University in St. Louis, St. Louis, MO 63130, United States. Electronic address: Blankenship@wustl.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Blankenship
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites; D003300:Copper / Q000737:chemistry*; D008667:Metalloproteins / Q000737:chemistry* / Q000235:genetics; D016297:Mutagenesis, Site-Directed / Q000379:methods
chemical_list: D001426:Bacterial Proteins; D008667:Metalloproteins; C073756:auracyanin A protein, bacteria; D003300:Copper
keywords: Blue copper proteins; Chloroflexus aurantiacus; Cupredoxins; Electron transport; Metalloproteins