The pathway of CO binding to cytochrome c oxidase Can the gateway be closed?

FEBS Letters

Hill, Bruce C.¹ 

[1] Department of Biochemistry, Queen's University, Kingston, Ont. K7L 3N6, Canada

关键词: Cytochrome c oxidase;    Ligand binding;    Binuclear center;    Cytochrome a 3-CuB;    Cyanide;    Carbon monoxide;    FTIR;    Fourier transform infrared;    TMPD;    N;    N;    N′;    N′-tetramethyl-p-phenylenediamine;   

DOI  :  10.1016/0014-5793(94)01140-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Addition of cyanide to the CO complex of cytochrome oxidase reduces the apparent photosensitivity of the Fe–CO bond. This effect is not seen with azide, or when cyanide is added to ferromyoglobin-CO. It is proposed that cyanide binds to Cu_B, and restricts the passage of CO out of the protein. This restriction favors geminate recombination of CO and ferrocytochrome a ₃, thereby lowering the apparent quantum yield for CO photolysis. The apparent K _d of cyanide for Cu_B is 15.4 mM. These data support a direct role for Cu_B in ligand binding by cytochrome c oxidase.

【 授权许可】

Unknown