InterPro domain: IPR002387

Blue or 'type-1' copper proteins are small proteins which bind a singlecopper atom and which are characterised by an intense electronic absorptionband near 600 nm [ 1 , 2 ]. The most well known members of this class of proteins are the plant chloroplastic plastocyanins, and the distantly related bacterial azurins, which exchange electrons with cytochrome c551. Plastocyanin participates in electron transfer between the cytochrome b6f complex and photosystem I. Many cyanobacteria and eukaryotic algae can synthesise both plastocyanin and its functional analog cytochrome c6, depending on bioavailabilities of copper and iron, respectively [ 3 ].

Plastocyanin participates in electron transfer between P700 and the cytochrome b/f complex in photosystem I [ 4 ].

1. Solution structure of the type 1 blue copper protein amicyanin from Thiobacillus versutus. J. Mol. Biol. 240, 358-71
2. Evolution of protein complexity: the blue copper-containing oxidases and related proteins. J. Mol. Evol. 36, 41-66
3. Electron transfer between membrane complexes and soluble proteins in photosynthesis. Acc. Chem. Res. 36, 798-805
4. Plastocyanin: structural and functional analysis. J. Bioenerg. Biomembr. 26, 49-66