title: Glutamate-286 mutants of cytochrome bo-type ubiquinol oxidase from Escherichia coli: influence of mutations on the binuclear center structure revealed by FT-IR and EPR spectroscopies.
abstract: Glutamate-286 mutants of cytochrome bo-type ubiquinol oxidase from Escherichia coli were examined by EPR and FT-IR spectroscopies. We confirmed a very low enzymatic activity for E286Q. However, E286D retained one-third of the wild-type activity, probably due to the presence of the carboxylic group on the side-chain. The effect of the mutations at position 286 on the binuclear site was observed clearly in the EPR spectral change for the air-oxidized state. The effect was more significantly manifested in the presence of cyanide or azide in the oxidized state. In contrast, the mutations only slightly perturbed the binuclear center of the CO-reduced enzymes. These results indicate the importance of a direct through-bond connectivity between CuB and Glu286 via Pro285 and His284.
authors.affiliation: Department of Life Science, Faculty of Science, Himeji Institute of Technology, Hyogo, Japan. tsubaki@sci.himeji-tech.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Tsubaki
authors.forename: H
authors.initials: H
authors.lastname: Hori
authors.forename: T
authors.initials: T
authors.lastname: Mogi
mesh_terms: D001665:Binding Sites; D002248:Carbon Monoxide; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D018698:Glutamic Acid; D006639:Histidine; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D017354:Point Mutation; D011392:Proline; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
chemical_list: D011994:Recombinant Proteins; D018698:Glutamic Acid; D006639:Histidine; D002248:Carbon Monoxide; D011392:Proline; C038862:cytochrome o oxidase; D003576:Electron Transport Complex IV