Details

Autor(en) / Beteiligte

• Bhagi-Damodaran, Ambika
• Michael, Matthew A
• Zhu, Qianhong
• Reed, Julian
• Sandoval, Braddock A
• Mirts, Evan N
• Chakraborty, Saumen
• Moënne-Loccoz, Pierre
• Zhang, Yong
• Lu, Yi

Titel

Why copper is preferred over iron for oxygen activation and reduction in haem-copper oxidases

Ist Teil von

• Nature chemistry, 2017-03, Vol.9 (3), p.257

Ort / Verlag

England

Erscheinungsjahr

2017

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Haem-copper oxidase (HCO) catalyses the natural reduction of oxygen to water using a haem-copper centre. Despite decades of research on HCOs, the role of non-haem metal and the reason for nature's choice of copper over other metals such as iron remains unclear. Here, we use a biosynthetic model of HCO in myoglobin that selectively binds different non-haem metals to demonstrate 30-fold and 11-fold enhancements in the oxidase activity of Cu- and Fe-bound HCO mimics, respectively, as compared with Zn-bound mimics. Detailed electrochemical, kinetic and vibrational spectroscopic studies, in tandem with theoretical density functional theory calculations, demonstrate that the non-haem metal not only donates electrons to oxygen but also activates it for efficient O-O bond cleavage. Furthermore, the higher redox potential of copper and the enhanced weakening of the O-O bond from the higher electron density in the d orbital of copper are central to its higher oxidase activity over iron. This work resolves a long-standing question in bioenergetics, and renders a chemical-biological basis for the design of future oxygen-reduction catalysts.