title: Characterization of the Cytochrome c Membrane-Binding Site Using Cardiolipin-Containing Bicelles with NMR.
abstract: Cytochrome (cyt) c transports electrons from Complex III to Complex IV in mitochondria. Cyt c is ordinarily anchored to the mitochondrial membrane through interaction with cardiolipin (CL), however its release into the cytosol initiates apoptosis. The cyt c interaction site with CL-containing bicelles was characterized by NMR spectroscopy. Chemical shift perturbations in cyt c signals upon interaction with bicelles revealed that a relatively wide region, which includes the A-site, the CXXCH motif, and the N- and C-terminal helices, and contains multiple Lys residues, interacts cooperatively with CL. The specific cyt c-CL interaction increased with increasing CL molecules in the bicelles. The location of the cyt c interaction site for CL was similar to those for Complex III and Complex IV, thus indicating that cyt c recognizes lipids and partner proteins in a similar way. In addition to elucidating the cyt c membrane-binding site, these results provide insight into the dynamic aspect of cyt c interactions in mitochondria.
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan. s-nagao@ms.naist.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nagao
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan. hirota@ms.naist.jp.
authors.forename: Shun
authors.initials: S
authors.lastname: Hirota
mesh_terms: D001665:Binding Sites; D002308:Cardiolipins / Q000737:chemistry*; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D002308:Cardiolipins; D045304:Cytochromes c
keywords: bicelles; cytochrome c; membrane proteins; protein-lipid interaction; solution NMR