PDB ID or protein name

1hrc » Mitochondrial cytochrome c

1hrc » Mitochondrial cytochrome c
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Topology in Mitochondrial inner membrane
Topologyintermembrane space side
matrix space side
1hrc » Mitochondrial cytochrome c
Depth 2.1 ± 1.0 Å
Tilt Angle 80 ± 16°
ΔGtransfer -2.6 kcal/mol
Links to 1hrc PDB Sum, PDB, SCOP, MSD, OCA, MMDB
Topology intermembrane space
Resolution 1.9 Å
Other PDB entries representing this structure 1akk, 1crc, 1fi7, 1fi9, 1giw, 1i5t, 1lc1, 1lc2, 1m60, 1ocd, 1u75, 2frc, 2giw, 2pcb
Number of subunits 1
Experimental Verification for 1hrc » Mitochondrial cytochrome c
Calculated orientation is similar for all water-soluble cytochromes c. It is the same as an orientation of the closely related cytochrome c2 in the photosynthetic reaction center from Rhodobacter sphaeroides (PDB entry 1l9b). Calculated orientation corresponds to the binding mode proposed by Rytomaa and Kinnunen (1995), but differs from the binding mode proposed by Brown and Wuthrich (1977). Also, calculated orientation is in agreement with the following data: (a) membrane-binding side includes K86, K87, and K72 residues (Kostrewa et al. 2000); (b) cytochrome c inserts into lipid bilayer up to the level of initial methylenes (Domanov et al. 2005); and (c) heme is accessible to lipid phosphates (Pinheiro and Watts 1994). Experimental membrane binding affinity varies from -3.3 to -5.3 kcal/mol (0.1 M KCl) depending on the type of anionic lipid (Rietveld et al. 1983, Sankaram and Marsh 1993). Note that more remotely related cytochromes c from mitochondrial bc1 complexes (subunits D from 1kb9, 1pp9, etc.) have an additional C-terminal TM helix and adopt an opposite orientation with respect to the membrane. These cytochromes have a distinctly differnt arrangement of positively charged residues, which follows the negatively charged membrane surface.
7 references
Brown LR, Wuthrich K. 1977. NMR and ESR studies of the interactions of cytochrome c with mixed cardiolipin-phosphatidylcholine vesicles. Biochim Biophys Acta. 468:389-410. PubMed
Domanov YA, Molotkovsky JG, Gorbenko GP. 2005. Coverage-dependent changes of cytochrome c transverse location in phospholipid membranes revealed by FRET. Biochim Biophys Acta. 1716:49-58. PubMed
Kostrzewa, A., Pali, T., Froncisz, W., and Marsh, D. 2000. Membrane location of spin-labeled cytochrome c determined by paramagnetic relaxation agents. Biochemistry. 39:6066-6074. PubMed
Pinheiro TJ, Watts A. 1994. Lipid specificity in the interaction of cytochrome c with anionic phospholipid bilayers revealed by solid-state 31P NMR. Biochemistry. 33:2451-8. PubMed
Rietveld A, Sijens P, Verkleij AJ, Kruijff BD. 1983. Interaction of cytochrome c and its precursor apocytochrome c with various phospholipids. EMBO J. 2:907-913. PubMed
Rytomaa M, Kinnunen PK. 1995. Reversibility of the binding of cytochrome c to liposomes. Implications for lipid-protein interactions. J Biol Chem. 270:3197-202. PubMed
Sankaram MB and Marsh D. 1993. Protein-lipid interactions with peripheral membrane proteins. In: Protein-lipid interactions (Ed. A. Watts), Elsevier, 1993, pp. 127-162.
Comments on 1hrc » Mitochondrial cytochrome c
Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain.