The phenomenon of UV-Vis spectroscopic changing due the binding of CO to the nitric oxide reductase from Bacillus Azotoformans

13th Joint Conference on Chemistry

Suharti, Suharti^1

Department of Chemistry, Faculty of Mathematics and Sciences, Universitas Negeri Malang, East Java, Malang, Indonesia^1

关键词: Chloride concentrations;    Cytochrome c oxidase;    Gram-positive bacterium;    Heme iron;    Nitric oxide reductase;    Oxidation of CO;    Raman resonances;    UV-vis spectra;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/509/1/012141/pdf
DOI  :  10.1088/1757-899X/509/1/012141

来源: IOP

【 摘 要 】

Gram-positive bacterium, Bacillus azotoformans, possess a nitric oxide reductase named CuANOR (formerly qCuANOR). The purified enzyme consists of two subunits. On the basis of UV-Vis and EPR spectra, it was elucidated that its small subunit contains the mixed-valence dinuclear CuA center and its large subunit of CuANOR contains a low-spin heme b centre, a high-spin heme b and one nonheme iron centre. The latter two grouped is an EPR-silent binuclear iron centre where NO reduction occurred. The CuANOR revealed itself as a new class of nitric oxide reductase, a new member of cytochrome c oxidase superfamily. The structure of CuANOR is not available yet. Previous studies on Raman resonance and FTIR demonstrated the capability of both heme iron and non heme-iron to bind one CO molecule each in the highly free chloride of dithionite-reduced CuANOR, whereas at high chloride concentration the binding of CO at non-heme iron was lost. Whether the binding of CO to CuANOR is followed by the oxidation of CO to CO2, as found in cytochrome c oxidase, hemoglobin, myoglobin, and free heme, has never been reported. This paper reports the phenomenon of UV-Vis spectroscopic changing due the binding of CO to CuANOR which explain the enzyme reactivity toward CO molecule.