MALDI-TOF MS Lipid Profiles of Cytochrome c Oxidases: Cardiolipin Is Not an Essential Component of the Paracoccus denitrificans Oxidase

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• 作者：Rita Vitale ; Roberto Angelini ; Simona Lobasso ; Giuseppe Capitanio ; Bernd Ludwig ; Angela Corcelli
• 刊名：Biochemistry
• 出版年：2015
• 出版时间：February 3, 2015
• 年：2015
• 卷：54
• 期：4
• 页码：1144-1150
• 全文大小：291K
• ISSN：1520-4995

文摘

Lipids of cytochrome c oxidase (COX) of Paracoccus denitrificans have been identified by MALDI-TOF MS direct analyses of isolated protein complexes, avoiding steps of lipid extraction or chromatographic separation. Two different COX preparations have been considered in this study: the enzyme core consisting of subunits I and II (COX 2-SU) and the complete complex comprising all four subunits (COX 4-SU). In addition, MALDI-TOF MS lipid profiles of bacterial COX are also compared with those of the isolated mitochondrial COX and bacterial bc₁ complex. We show that the main lipids associated with bacterial COX 4-SU are phosphatidylglycerol (PG) and phosphatidylcholine (PC), and minor amounts of cardiolipin (CL). PG and PC are absent in the COX 2-SU preparation lacking subunits III and IV, whereas CL is still present. Quantitative analyses indicate that at variance from mitochondrial COX, cardiolipin is present in substoichiometric amounts in bacterial COX, at a CL:COX molar ratio of 鈭?:10. We conclude that bacterial COX does not require CL for structure or its activity.