Protein Domain : Cytochrome c, class ID IPR002324

Type	Family
Description	Cytochromes c (cytC) can be defined as electron-transfer proteins having one or several haem 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. CytC possess a wide range of properties and function in a large number of different redox processes. Ambler [ ] recognised four classes of cytC.Class I includes the low-spin soluble cytC of mitochondria and bacteria, with the haem-attachment sitetowards the N terminus, and the sixth ligand provided by a methionine residue about 40 residues further on towards the C terminus. On the basisof sequence similarity, class I cytC were further subdivided into five classes, IA to IE.Class ID (cyt c8) includes such bacterial proteins as Pseudomonas spp. cyt c-551, Hydrogenobacter thermophilus cyt c-552 and Rhodocyclus tenuis (Rhodospirillum tenue) cyt c-553 []. Sequence characteristics include severalPro residues around the sixth ligand Met, and a conserved Trp residue near the C terminus.The 3D structures of cyt C-551 from Pseudomonas aeruginosa and Pseudomonas stutzeri have been determined [ ]. The proteins consist of 5 α-helices;three 'core' helices form a 'basket' around the haem group, with one haem edge exposed to the solvent.
Short Name	Cyt_c_ID