title: Electrochemistry of cytochrome c immobilized on cardiolipin-modified electrodes: a probe for protein-lipid interactions.
abstract: Electrochemistry of cytochrome c (cyt c) immobilized on a cardiolipin (CL)/phosphatidylcholine (PC) film supported on a glassy carbon electrode was investigated using variable-frequency AC voltammetry. At low ionic strength, we observed two redox-active subpopulations characterized by distinct values of potential (E1/2) and electron transfer rate constant (k(ET)). At high ionic strength, only one subpopulation was detected, consistent with the existence of very stable cyt c-CL adducts, most probably formed by hydrophobic interactions between the protein and the fatty acid (FA) chains carried by CL. This subpopulation exhibits a comparatively high k(ET) value (> 300 s(-1)) apparently changing with the structure of the FA chains of CL, i.e. 18:2(n - 6) or 14:0. Our study suggests that electrochemistry can be a useful technique for probing protein-lipid interactions, and more particularly the role played by the specific structure of the FA chains of CL on cyt c binding.
authors.affiliation: CEMCA, UMR 6521, CNRS, Université de Bretagne Occidentale, Brest, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Perhirin
authors.forename: Edouardb
authors.initials: E
authors.lastname: Kraffe
authors.forename: Yanic
authors.initials: Y
authors.lastname: Marty
authors.forename: François
authors.initials: F
authors.lastname: Quentel
authors.forename: Philippe
authors.initials: P
authors.lastname: Elies
authors.forename: Frederic
authors.initials: F
authors.lastname: Gloaguen
mesh_terms: D002244:Carbon / Q000737:chemistry; D002308:Cardiolipins / Q000737:chemistry*; D045304:Cytochromes c / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D004579:Electron Transport; D057927:Hydrophobic and Hydrophilic Interactions; D055767:Immobilized Proteins / Q000737:chemistry*; D007700:Kinetics; D018625:Microscopy, Atomic Force; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D002308:Cardiolipins; D055767:Immobilized Proteins; D010713:Phosphatidylcholines; D002244:Carbon; D045304:Cytochromes c