FEBS Letters | |
Fourier‐transform infrared studies on azide‐binding to the binuclear center of the Escherichia coli bo‐type ubiquinol oxidase 1 | |
Mogi, Tatsushi1  Hori, Hiroshi2  Tsubaki, Motonari3  | |
[1] Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan;Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigoori-cho, Akou-gun, Hyogo 678-1297, Japan | |
关键词: Escherichia coli bo-type ubiquinol oxidase; Fourier-transform infrared; Heme-copper binuclear center; Azide; Isotope label; Bridging structure; | |
DOI : 10.1016/S0014-5793(99)00423-8 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Azide-binding to the heme-copper binuclear center of bo-type ubiquinol oxidase from Escherichia coli was investigated with Fourier-transform infrared spectroscopy. Deconvolution analyses of infrared spectra of the azide (14N3)-inhibited air-oxidized form showed a major infrared azide antisymmetric stretching band at 2041 cm−1. An additional band developed at 2062.5 cm−1 during a longer incubation. Isotope substitutions with terminally 15N-labelled azides did not show a splitting of the major band, indicating that the geometry of the bound azide is mainly in a bridging configuration between high-spin heme o and CuB. The band at 2062.5 cm−1 showed clear splittings upon substitution with the terminally 15N-labelled azides, indicating the CuB 2+-N=N=N structure. Partial reduction of the oxidase with β-NADH in the presence of azide caused an appearance of new infrared bands at 2038.5 (major) and 2009 (minor) cm−1. The former band also showed clear splittings in the presence of the terminally 15N-labelled azides, indicating that reduction of low-spin heme b alters the structure of the binuclear center leading to the Feo 3+-N=N=N configuration.
【 授权许可】
Unknown
【 预 览 】
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