Protein Domain : Photosystem II cytochrome c-550 precursor IPR016003

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 1 cytochromes have the haem-attachment site towards the N terminus, and can be further subdivided into five groups (1A to 1E) based on sequence similarity. Cytochrome C550 (CytC550) is a class 1A cytochrome. CytC550 (also known as PsbV) is an extrinsic membrane protein that forms part of the oxygen-evolving complex in photosystem II, this complex being responsible for the splitting of water into O(2) and 4H+, the latter being used to reduce CO2 to glucose. CytC550 is only found in cyanobacteria and red algae [], this protein having been lost during the evolution of green plants []. Other Class 1A cytochrome C proteins include mitochondrial cytochrome C, which acts as an electron carrier between cytochrome reductase and the cytochrome oxidase complex, the final electron carrier in the mitochondrial electron transport chain; and cytochrome C6, which acts as an electron carrier between cytochrome b6f and photosystem I in cyanobacteria [].
Short Name	PSII_cyt_c550