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Cardiolipin dynamics and binding to conserved residues in the mitochondrial ADP/ATP carrier.

Accepted version
Peer-reviewed

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Authors

Duncan, Anna L 
Ruprecht, Jonathan J 
Kunji, Edmund RS 
Robinson, Alan J 

Abstract

Cardiolipin in eukaryotes is found in the mitochondrial inner membrane, where it interacts with membrane proteins and, although not essential, is necessary for the optimal activity of a number of proteins. One of them is the mitochondrial ADP/ATP carrier, which imports ADP into the mitochondrion and exports ATP. In the crystal structures, cardiolipin is bound to three equivalent sites of the ADP/ATP carrier, but its role is unresolved. Conservation of residues at these cardiolipin binding sites across other members of the mitochondrial carrier superfamily indicates cardiolipin binding is likely to be important for the function of all mitochondrial carriers. Multiscale simulations were performed in a cardiolipin-containing membrane to investigate the dynamics of cardiolipin around the yeast and bovine ADP/ATP carriers in a lipid bilayer and the properties of the cardiolipin-binding sites. In coarse-grain simulations, cardiolipin molecules bound to the carriers for longer periods of time than phosphatidylcholine and phosphatidylethanolamine lipids-with timescales in the tens of microseconds. Three long-lived cardiolipin binding sites overlapped with those in the crystal structures of the carriers. Other shorter-lived cardiolipin interaction sites were identified in both membrane leaflets. However, the timescales of the interactions were of the same order as phosphatidylcholine and phosphatidylethanolamine, suggesting that these sites are not specific for cardiolipin binding. The calculation of lipid binding times and the overlap of the cardiolipin binding sites between the structures and simulations demonstrate the potential of multiscale simulations to investigate the dynamics and behavior of lipids interacting with membrane proteins.

Description

Keywords

Adenine nucleotide translocator, Adenine nucleotide transporter, Cardiolipin, Mitochondria, Molecular dynamics simulation, Trimethyllysine, Amino Acid Sequence, Animals, Binding Sites, Cardiolipins, Cattle, Conserved Sequence, Mitochondria, Mitochondrial ADP, ATP Translocases, Mitochondrial Membranes, Models, Molecular, Molecular Dynamics Simulation, Protein Binding, Protein Interaction Domains and Motifs, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins

Journal Title

Biochim Biophys Acta Biomembr

Conference Name

Journal ISSN

0005-2736
1879-2642

Volume Title

1860

Publisher

Elsevier BV
Sponsorship
Medical Research Council (MC_U105674181)
Medical Research Council (MC_U105663139)
Biotechnology and Biological Sciences Research Council (BB/R50564X/1)
Medical Research Council (MC_UU_00015/1)
Medical Research Council (MC_UU_00015/7)