- Cytochrome f
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Apocytochr_F_C cytochrome f from the b6f complex of phormidium laminosum Identifiers Symbol Apocytochr_F_C Pfam PF01333 Pfam clan CL0105 InterPro IPR002325 PROSITE PDOC00169 SCOP 1ctm TCDB 3.D.3 Available protein structures: Pfam structures PDB RCSB PDB; PDBe PDBsum structure summary Cytochrome f is the largest subunit of cytochrome b6f complex (plastoquinol—plastocyanin reductase; EC 1.10.99.1). In its structure and functions, the cytochrome b6f complex bears extensive analogy to the cytochrome bc1 complex of mitochondria and photosynthetic purple bacteria. Cytochrome f (cyt f) plays a role analogous to that of cytochrome c1, in spite of their different structures.[1]
The 3D structure of Brassica rapa (Turnip) cyt f has been determined.[2] The lumen-side segment of cyt f includes two structural domains: a small one above a larger one that, in turn, is on top of the attachment to the membrane domain. The large domain consists of an anti-parallel beta-sandwich and a short haem-binding peptide, which form a three-layer structure. The small domain is inserted between beta-strands F and G of the large domain and is an all-beta domain. The haem nestles between two short helices at the N terminus of cyt f. Within the second helix is the sequence motif for the c-type cytochromes, CxxCH (residues 21-25), which is covalently attached to the haem through thioether bonds to Cys-21 and Cys-24. His-25 is the fifth haem iron ligand. The sixth haem iron ligand is the alpha-amino group of Tyr-1 in the first helix.[2] Cyt f has an internal network of water molecules that may function as a proton wire.[2] The water chain appears to be a conserved feature of cyt f.
References
- ^ Prince RC, George GN (June 1995). "Cytochrome f revealed". Trends Biochem. Sci. 20 (6): 217–8. PMID 7631417.
- ^ a b c Martinez SE, Huang D, Ponomarev M, Cramer WA, Smith JL (June 1996). "The heme redox center of chloroplast cytochrome f is linked to a buried five-water chain". Protein Sci. 5 (6): 1081–92. doi:10.1002/pro.5560050610. PMC 2143431. PMID 8762139. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2143431.
Further reading
- Bendall, D.S. (2004). "The unfinished story of cytochrome f". Photosynth. Res. 80 (1–3): 265–276. doi:10.1023/B:PRES.0000030454.23940.f9. PMID 16328825.
- Cramer, W.A., Martinez, S.E., Huang, D., Tae, G.S., Everly, R.M., Heymann, J.B., Cheng, R.H., Baker, T.S. and Smith, J.L. (1994). "Structural aspects of the cytochrome b6f complex; structure of the lumen-side domain of cytochrome f". J. Bioenerg. Biomembr. 26 (1): 31–47. doi:10.1007/BF00763218. PMID 8027021.
External links
- PDB 1CTM - X-ray structure of lumen-side domain of cytochrome f from turnip (Brassica rapa)
- PDB 1CFM - X-ray structure of lumen-side domain of cytochrome f from Chlamydomonas reinhardtii
- PDB 1CI3 - X-ray tructure of soluble domain of cytochrome f from cyanobacterium Phormidium laminosum
- IPR002325 - InterPro entry for cytochrome f
- MeSH Cytochrome+f
This article includes text from the public domain Pfam and InterPro IPR002325
Categories:- Photosynthesis
- Cytochromes
- Peripheral membrane proteins
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