FEBS Letters | |
CuB promotes both binding and reduction of dioxygen at the heme‐copper binuclear center in the Escherichia coli bo‐type ubiquinol oxidase | |
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 CuB-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 CuB seems to have endowed the mutant enzyme with myoglobin-like properties, thereby stabilizing the CO-bound form, too. Accordingly we conclude that CuB plays a pivotal role in preferential trapping and efficient reduction of dioxygen at the heme-copper binuclear center.
【 授权许可】
Unknown
【 预 览 】
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