Structures and physiological roles of 13 integral lipids of bovine heart cytochrome c oxidase

• Published in: The EMBO journal Vol. 26; no. 6; pp. 1713 - 1725
• Main Authors: Shinzawa-Itoh, Kyoko, Aoyama, Hiroshi, Muramoto, Kazumasa, Terada, Hirohito, Kurauchi, Tsuyoshi, Tadehara, Yoshiki, Yamasaki, Akiko, Sugimura, Takashi, Kurono, Sadamu, Tsujimoto, Kazuo, Mizushima, Tsunehiro, Yamashita, Eiki, Tsukihara, Tomitake, Yoshikawa, Shinya
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 21.03.2007; Blackwell Publishing Ltd; Nature Publishing Group
• Subjects: Absorptiometry, Photon; Anatomy & physiology; Animals; Binding sites; Binding Sites - genetics; Cattle; Chromatography, Gas; Cytochrome; cytochrome c oxidase; Electron Transport Complex IV - chemistry; Electron Transport Complex IV - metabolism; Electron Transport Complex IV - physiology; Evolution, Molecular; fatty acid structure; Fatty acids; Heart; Lipids; Lipids - analysis; Mass spectrometry; Membranes; Models, Molecular; Molecular biology; Molecular Structure; Myocardium - enzymology; Oleic Acids - analysis; Paracoccus denitrificans; Paracoccus denitrificans - chemistry; phospholipids; Proteins; Tandem Mass Spectrometry; X-ray structural analysis; X-rays
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1038/sj.emboj.7601618

All 13 lipids, including two cardiolipins, one phosphatidylcholine, three phosphatidylethanolamines, four phosphatidylglycerols and three triglycerides, were identified in a crystalline bovine heart cytochrome c oxidase (CcO) preparation. The chain lengths and unsaturated bond positions of the fatty acid moieties determined by mass spectrometry suggest that each lipid head group identifies its specific binding site within CcOs. The X‐ray structure demonstrates that the flexibility of the fatty acid tails facilitates their effective space‐filling functions and that the four phospholipids stabilize the CcO dimer. Binding of dicyclohexylcarbodiimide to the O2 transfer pathway of CcO causes two palmitate tails of phosphatidylglycerols to block the pathway, suggesting that the palmitates control the O2 transfer process.The phosphatidylglycerol with vaccenate (cis‐Δ11‐octadecenoate) was found in CcOs of bovine and Paracoccus denitrificans, the ancestor of mitochondrion, indicating that the vaccenate is conserved in bovine CcO in spite of the abundance of oleate (cis‐Δ9‐octadecenoate). The X‐ray structure indicates that the protein moiety selects cis‐vaccenate near the O2 transfer pathway against trans‐vaccenate. These results suggest that vaccenate plays a critical role in the O2 transfer mechanism.