CuB promotes both binding and reduction of dioxygen at the heme‐copper binuclear center in the Escherichia coli bo‐type ubiquinol oxidase
Authors:
- Tomoyasu HiranoTHTomoyasu Hirano
- Hiro NakamuraHNHiro Nakamura
- 21 August 1995
- journal article
- Published by Wiley in FEBS Letters
- Vol. 370 (3) , 259-263
Abstract
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.Keywords
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