Crystal Structure of Fully Oxidized Bovine Heart Cytochrome c Oxidase at 2.8 Angstrom Resolution: a Review

S. Yoshikawa,^1,2 T. Tsukihara,³ and K. Shinzawa-Itoh¹

¹Department of Life Science, Himeji Institute of Technology, Kamigohri, Akoh Hyogo 678-12, Japan; fax: 81-7915-8-0132; E-mail: yoshi@sci.himeji-tech.ac.jp

²To whom correspondence should be addressed.

³Institute for Protein Research, Osaka University, Yamada-Kami Suita, Osaka, Japan; fax: 81-6-879-8606.

Submitted July 17, 1996.

Structural and functional studies on cytochrome c oxidase before the crystal structures appeared are summarized to show the importance of X-ray crystal structure at atomic resolution for understanding the mechanism of the enzyme reaction, O₂ reduction coupled with proton pumping. The crystal structure of the bovine heart enzyme in the fully oxidized state at 2.8 Angstrom resolution are reviewed to evaluate its contribution for understanding the enzyme reaction mechanism. Effects of detergent structure on the crystallization conditions of bovine heart cytochrome c oxidase, which were critical for obtaining the X-ray crystal structure, are presented to propose a possible mechanism of crystallization of multicomponent membrane proteins.

KEY WORDS: cytochrome c oxidase, crystal structure, membrane protein, crystallization, mitochondrial respiration, O₂ reduction mechanism, proton pumping, nonionic detergent, biological oxidation, electron transfer, bioenergetics, O₂ channel, water channel.

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