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

FEBS Letters

Mogi, Tatsushi²  Hori, Hiroshi¹  Tsubaki, Motonari³ 

[1] Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560, Japan;Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan;Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigoori-cho, Akou-gun, Hyogo 678-12, Japan

关键词: Heme-copper terminal quinol oxidase;    Cytochrome bo;    Site-directed mutagenesis;    Proton channel;    EPR spectroscopy;    FT-IR spectroscopy;    EPR;    electron paramagnetic resonance;    FT-IR;    Fourier-transform infrared;    H-bond;    hydrogen bond;   

DOI  :  10.1016/S0014-5793(97)01218-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 Cu_B and Glu²⁸⁶ via Pro²⁸⁵ and His²⁸⁴.

【 授权许可】

Unknown