2N3B

Structure of oxidized horse heart cytochrome c encapsulated in reverse micelles

Summary for 2N3B

• Entry DOI: 10.2210/pdb2n3b/pdb
• Related: 1OCD
• NMR Information: BMRB: 25640
• Descriptor: Cytochrome c, HEME C (3 entities in total)
• Functional Keywords: reverse micelle, structural water, paramagnetic, electron transport
• Biological source: Equus caballus (domestic horse,equine)
• Cellular location: Mitochondrion intermembrane space: P00004
• Total number of polymer chains: 1
• Total formula weight: 12344.10

Authors

O'Brien, E.S.,Nucci, N.V.,Fuglestad, B.,Tommos, C.,Wand, A. (deposition date: 2015-05-27, release date: 2015-10-28, Last modification date: 2024-10-16)

Primary citation

O'Brien, E.S.,Nucci, N.V.,Fuglestad, B.,Tommos, C.,Wand, A.J.
Defining the Apoptotic Trigger: THE INTERACTION OF CYTOCHROME c AND CARDIOLIPIN.
J.Biol.Chem., 290:30879-30887, 2015

PubMed Abstract: The interaction between cytochrome c and the anionic lipid cardiolipin has been proposed as a primary event in the apoptotic signaling cascade. Numerous studies that have examined the interaction of cytochrome c with cardiolipin embedded in a variety of model phospholipid membranes have suggested that partial unfolding of the protein is a precursor to the apoptotic response. However, these studies lacked site resolution and used model systems with negligible or a positive membrane curvature, which is distinct from the large negative curvature of the invaginations of the inner mitochondrial membrane where cytochrome c resides. We have used reverse micelle encapsulation to mimic the potential effects of confinement on the interaction of cytochrome c with cardiolipin. Encapsulation of oxidized horse cytochrome c in 1-decanoyl-rac-glycerol/lauryldimethylamine-N-oxide/hexanol reverse micelles prepared in pentane yields NMR spectra essentially identical to the protein in free aqueous solution. The structure of encapsulated ferricytochrome c was determined to high precision (bb ∼ 0.23 Å) using NMR-based methods and is closely similar to the cryogenic crystal structure (bb ∼ 1.2 Å). Incorporation of cardiolipin into the reverse micelle surfactant shell causes localized chemical shift perturbations of the encapsulated protein, providing the first view of the cardiolipin/cytochrome c interaction interface at atomic resolution. Three distinct sites of interaction are detected: the so-called A- and L-sites, plus a previously undocumented interaction centered on residues Phe-36, Gly-37, Thr-58, Trp-59, and Lys-60. Importantly, in distinct contrast to earlier studies of this interaction, the protein is not significantly disturbed by the binding of cardiolipin in the context of the reverse micelle.

PubMed: 26487716
DOI: 10.1074/jbc.M115.689406

Experimental method

SOLUTION NMR