CuB promotes both binding and reduction of dioxygen at the heme‐copper binuclear center in the Escherichia coli bo‐type ubiquinol oxidase

FEBS Letters

关键词: E. coli bo-type ubiquinol oxidase;    Heme-copper binuclear center;    CuB-deficient mutant;    Intramolecular electron transfer;    Dioxygen reduction chemistry;    UQO;    the E. coli bo-type ubiquinol oxidase;    H333A;    subunit I mutant where His333 had been substituted with alanine;   

DOI  :  10.1016/0014-5793(95)00852-Z

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A Cu_B-deficient mutant of the Escherichia coli bo-type ubiquinol oxidase exhibits a very low oxidase activity that is consistent with a decreased dioxygen binding rate. During the turnover, a photolabile reaction intermediate persists for a few hundred milliseconds, due to much slower heme o-to-ligand electron transfer. Thus, the lack of Cu_B seems to have endowed the mutant enzyme with myoglobin-like properties, thereby stabilizing the CO-bound form, too. Accordingly we conclude that Cu_B plays a pivotal role in preferential trapping and efficient reduction of dioxygen at the heme-copper binuclear center.

【 授权许可】

Unknown