Two-dimensional infrared correlation spectroscopy study of the interaction of oxidized and reduced cytochrome c with phospholipid model membranes.
We have used two-dimensional infrared correlation spectroscopy (2D-IR) to study the interaction and conformation of cytochrome c in the presence of a binary phospholipid mixture composed of a zwitterionic perdeuterated phospholipid and a negatively-charged one. The influence of the main temperature phase transition of the phospholipid model membranes on the conformation of cytochrome c has been evaluated by monitoring both the Amide I' band of the protein and the CH(2) and CD(2) stretching bands of the phospholipids. Synchronous 2D-IR analysis has been used to determine the different secondary structure components of cytochrome c which are involved in the specific interaction with the phospholipids, revealing the existence of a specific interaction between the protein with cardiolipin-containing vesicles but not with phosphatidic acid-containing ones. Interestingly, 2D-IR is capable of showing the existence of significant changes in the protein conformation at the same time that the phospholipid transition occurs. In summary, 2D-IR revealed an important effect of the phospholipid phase transition of cardiolipin on the secondary structure of oxidized cytochrome c but not to either reduced cytochrome c or in the presence of phosphatidic acid, demonstrating the existence of specific intermolecular interactions between cardiolipin and cytochrome c.
Bernabeu
Angela
A
Instituto de Biología Molecular y Celular, Universidad "Miguel Hernández", E-03202 Elche-Alicante, Spain.
Contreras
Lellys M
LM
Villalaín
José
J
D045304:Cytochromes c / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013055:Spectrophotometry, Infrared
D008051:Lipid Bilayers; D010743:Phospholipids; D045304:Cytochromes c