Structures and physiological roles of 13 integral lipids of bovine heart cytochrome c oxidase
Structures and physiological roles of 13 integral lipids of bovine heart cytochrome c oxidase
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DOI：
10.1038/sj.emboj.7601618
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发表时间：
2007-03-21
期刊：
影响因子：
11.4
通讯作者：
Yoshikawa, Shinya
中科院分区：
文献类型：
--
作者：
Shinzawa-Itoh, Kyoko;Aoyama, Hiroshi;Yoshikawa, Shinya
所有13种脂质，包括两种心磷脂，一种磷脂酰胆碱，三种磷脂酰乙醇胺，四种磷脂酰甘油和三种甘油三酯，在结晶牛心细胞色素c氧化酶（CcO）制剂中鉴定。通过质谱法测定的脂肪酸部分的链长和不饱和键的位置表明，每个脂质头基确定其特定的结合位点内CCO。的X-射线结构表明，灵活性的脂肪酸尾巴，促进其有效的空间填充功能和四个磷脂稳定的CCO二聚体。二环己基碳二亚胺与CcO的O-2转移途径的结合导致磷脂酰甘油的两个棕榈酸酯尾部阻断该途径，表明棕榈酸酯控制O-2转移过程。在牛和Paracoccus acidificans（Paracoccus acidificans）的CcO中发现了含有疫苗酸盐（顺式-δ（11）-十八碳烯酸盐）的磷脂酰甘油，这表明尽管油酸盐（顺式-D9-十八碳烯酸盐）丰富，但疫苗酸盐在牛CcO中是保守的。X-射线结构表明，蛋白质部分选择顺式疫苗附近的O-2转移途径对反式疫苗。这些结果表明，疫苗接种在O-2传递机制中起着关键作用。
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 O-2 transfer pathway of CcO causes two palmitate tails of phosphatidylglycerols to block the pathway, suggesting that the palmitates control the O-2 transfer process. The phosphatidylglycerol with vaccenate (cis-Delta(11)-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-D9-octadecenoate). The X-ray structure indicates that the protein moiety selects cis-vaccenate near the O-2 transfer pathway against trans-vaccenate. These results suggest that vaccenate plays a critical role in the O-2 transfer mechanism.