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Dimer interface of Bovine cytochrome c oxidase is influenced by local posttranslational modifications and lipid binding

Abstract:
Bovine cytochrome c oxidase is an integral membrane protein complex comprising 13 protein subunits and associated lipids. Dimerization of the complex has been proposed; however, definitive evidence for the dimer is lacking. We used advanced mass spectrometry methods to investigate the oligomeric state of cytochrome c oxidase and the potential role of lipids and posttranslational modifications in its subunit interfaces. Mass spectrometry of the intact protein complex revealed that both the monomer and the dimer are stabilized by large lipid entities. We identified these lipid species from the purified protein complex, thus implying that they interact specifically with the enzyme. We further identified phosphorylation and acetylation sites of cytochrome c oxidase, located in the peripheral subunits and in the dimer interface, respectively. Comparing our phosphorylation and acetylation sites with those found in previous studies of bovine, mouse, rat, and human cytochrome c oxidase, we found that whereas some acetylation sites within the dimer interface are conserved, suggesting a role for regulation and stabilization of the dimer, phosphorylation sites were less conserved and more transient. Our results therefore provide insights into the locations and interactions of lipids with acetylated residues within the dimer interface of this enzyme, and thereby contribute to a better understanding of its structure in the natural membrane. Moreover dimeric cytochrome c oxidase, comprising 20 transmembrane, six extramembrane subunits, and associated lipids, represents the largest integral membrane protein complex that has been transferred via electrospray intact into the gas phase of a mass spectrometer, representing a significant technological advance.
Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1073/pnas.1600354113

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Institution:
University of Oxford
Division:
MPLS
Department:
Chemistry
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MPLS
Department:
Chemistry
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
Biochemistry
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MPLS
Department:
Chemistry
Role:
Author


Publisher:
National Academy of Sciences
Journal:
Proceedings of the National Academy of Sciences of the United States of America More from this journal
Volume:
113
Issue:
29
Pages:
8230-8235
Publication date:
2016-07-19
Acceptance date:
2016-06-13
DOI:
EISSN:
1091-6490
ISSN:
0027-8424


Language:
English
Keywords:
Pubs id:
pubs:628392
UUID:
uuid:a1d7fbe4-c36f-4783-b7cf-45498dd3d1c2
Local pid:
pubs:628392
Source identifiers:
628392
Deposit date:
2016-08-11

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