Cytochrome c family
| Cytochrome c | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Structure of cytochrome c2 from Rhodopseudomonas viridis.[1] | |||||||||
| Identifiers | |||||||||
| Symbol | Cytochrom_C | ||||||||
| Pfam | PF00034 | ||||||||
| InterPro | IPR003088 | ||||||||
| PROSITE | PDOC00169 | ||||||||
| SCOP | 1cry | ||||||||
| SUPERFAMILY | 1cry | ||||||||
| OPM superfamily | 78 | ||||||||
| OPM protein | 1hrc | ||||||||
| |||||||||
| Cytochrome C' | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 atomic structure of a cytochrome c' with an unusual ligand-controlled dimer dissociation at 1.8 angstroms resolution | |||||||||
| Identifiers | |||||||||
| Symbol | Cytochrom_C_2 | ||||||||
| Pfam | PF01322 | ||||||||
| InterPro | IPR002321 | ||||||||
| PROSITE | PDOC00169 | ||||||||
| SCOP | 1cgo | ||||||||
| SUPERFAMILY | 1cgo | ||||||||
| |||||||||
| Class III cytochrome C family | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 sulfate respiration in desulfovibrio vulgaris hildenborough: structure of the 16-heme cytochrome c hmca at 2.5 a resolution and a view of its role in transmembrane electron transfer | |||||||||
| Identifiers | |||||||||
| Symbol | Cytochrom_CIII | ||||||||
| Pfam | PF02085 | ||||||||
| Pfam clan | CL0317 | ||||||||
| InterPro | IPR020942 | ||||||||
| SCOP | 2cdv | ||||||||
| SUPERFAMILY | 2cdv | ||||||||
| CDD | cd08168 | ||||||||
| |||||||||
Cytochromes c (cytC) are electron-transfer proteins having one or several heme c groups, bound to the protein by one or, more generally, two thioether bonds involving sulphydryl groups of cysteine residues. The fifth haem iron ligand is always provided by a histidine residue. Cytochromes c possess a wide range of properties and function in a large number of different redox processes.[2] The founding member of this family is mitochondrial cytochrome c.
Ambler[3] recognized four classes of cytC.
- Class I includes the low-spin soluble cytC of mitochondria and bacteria, with the haem-attachment site towards the N-terminus, and the sixth ligand provided by a methionine residue about 40 residues further on towards the C-terminus. On the basis of sequence similarity, class I cytC were further subdivided into five classes, IA to IE. Class IB includes the eukaryotic mitochondrial cytC and prokaryotic 'short' cyt c2 exemplified by Rhodopila globiformis cyt c2; class IA includes 'long' cyt c2, such as Rhodospirillum rubrum cyt c2 and Aquaspirillum itersonii cytc-550, which have several extra loops by comparison with class IB cytC.
- Class II includes the high-spin cytC' and a number of low-spin cytochromes, e.g. cyt c-556. The haem-attachment site is close to the C terminus. The cytC' are capable of binding such ligands as CO, NO or CN(-), albeit with rate and equilibrium constants 100 to 1,000,000-fold smaller than other high-spin haemoproteins.[4] This, coupled with its relatively low redox potential, makes it unlikely that cytC' is a terminal oxidase. Thus cytC' probably functions as an electron transfer protein.[5] The 3D structures of a number of cytC' have been determined. The molecule usually exists as a dimer, each monomer folding as a four-alpha-helix bundle incorporating a covalently-bound haem group at the core.[5] The Chromatium vinosum cytC' exhibits dimer dissociation upon ligand binding.[6]
- Class III comprises the low redox potential multiple haem cytochromes: cyt C7 (trihaem), C3 (tetrahaem), and high-molecular-weight cytC, HMC (hexadecahaem), with only 30-40 residues per haem group. The haem c groups, all bis-histidinyl coordinated, are structurally and functionally nonequivalent and present different redox potentials in the range 0 to -400 mV.[7] The 3D structures of a number of cyt C3 proteins have been determined. The proteins consist of 4-5 alpha-helices and 2 beta-strands wrapped around a compact core of four non-parallel haems, which present a relatively high degree of exposure to the solvent. The overall protein architecture, haem plane orientations and iron-iron distances are highly conserved.[7]
- Class IV includes complex proteins containing other prosthetic groups besides haem c, such as flavocytochromes c and cytochromes cd.[3]
Subfamilies
Human proteins containing this domain
CYCS;
References
- ↑ Miki K, Sogabe S, Uno A, et al. (May 1994). "Application of an automatic molecular-replacement procedure to crystal structure analysis of cytochrome c2 from Rhodopseudomonas viridis". Acta Crystallogr. D. 50 (Pt 3): 271–5. doi:10.1107/S0907444993013952. PMID 15299438.
- ↑ Moore GR, Pettigrew GW (1987). : –. Missing or empty
|title=(help) - 1 2 Ambler RP (1991). "Sequence variability in bacterial cytochromes c". Biochim. Biophys. Acta. 1058 (1): 42–47. doi:10.1016/S0005-2728(05)80266-X. PMID 1646017.
- ↑ Kassner RJ (May 1991). "Ligand binding properties of cytochromes c'". Biochim. Biophys. Acta. 1058 (1): 8–12. doi:10.1016/s0005-2728(05)80257-9. PMID 1646027.
- 1 2 Moore GR (May 1991). "Bacterial 4-alpha-helical bundle cytochromes". Biochim. Biophys. Acta. 1058 (1): 38–41. doi:10.1016/s0005-2728(05)80265-8. PMID 1646016.
- ↑ Ren Z, Meyer T, McRee DE (November 1993). "Atomic structure of a cytochrome c' with an unusual ligand-controlled dimer dissociation at 1.8 A resolution". J. Mol. Biol. 234 (2): 433–45. doi:10.1006/jmbi.1993.1597. PMID 8230224.
- 1 2 Coutinho IB, Xavier AV (1994). "Tetraheme cytochromes". Meth. Enzymol. 243: 119–40. doi:10.1016/0076-6879(94)43011-X. PMID 7830606.
This article incorporates text from the public domain Pfam and InterPro IPR002321
This article incorporates text from the public domain Pfam and InterPro IPR020942
This article is issued from Wikipedia - version of the 6/29/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.