Conformational change of cytochrome a 3 induced by oxidized cytochrome c

FEBS Letters

Musatov, Andrey¹  Konstantinov, Alexander A.¹ 

[1]Laboratory of Biophysics, Institute of Experimental Physics, Slovac Acad. Sci. Solovjevova 47, 043 53 Košice, Czechoslovakia

关键词: Cytochrome c-oxidase;    Cyanide binding;    Conformational change;    CuB-site;    Cytochrome c;    Poly-L-lysine;   

DOI  :  10.1016/0014-5793(88)80500-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cyanide binding with the oxidized resting Yonetani-type cytochrome c-oxidase followed spectrophotometrically reveals a relatively rapid initial phase the rate of which shows saturation behaviour with respect to [HCN] and secondary slower absorption changes to a first approximation independent of the ligand concentration. Oxidized cytochrome c greatly accelerates the initial phase of cyanide binding but does not affect significantly contribution or rate constant of the slow phase. The same effect is exerted by poly-L-lysine. Within a framework of a reaction mechanism assuming Cu²⁺ _B to be the initial HCN-binding site, cytochrome c ³⁺ and other polycations are likely to bring about a conformational change of cytochrome oxidase resulting in an increased affinity of Cu²⁺ _B for HCN. This could occur by virtue of loosening a bond between Cu²⁺ _B and one of its endogenous ligands facilitating displacement of the latter by HCN.

【 授权许可】

Unknown