Binding Site

Blue (type 1) copper protein, binding site (IPR028871)

Short name: BlueCu_1_BS


Blue (type 1) copper proteins constitute a diverse class of proteins, including small blue proteins and multicopper oxidases. They bind copper and are characterised by an intense electronic absorption band near 600 nm [PMID: 6698995, PMID: 8433378].

The most well known members of this class of proteins are the small blue proteins, which includes azurins and plastocyanins. It is a group of monomeric proteins which contain one copper ion per molecule. The plant chloroplastic plastocyanins exchange electrons with cytochrome c6, and the distantly related bacterial azurins exchange electrons with cytochrome c551. This group also includes amicyanin from bacteria such as Methylobacterium extorquens or Paracoccus versutus (Thiobacillus versutus) that can grow on methylamine; auracyanins A and B from Chloroflexus aurantiacus [PMID: 1313011]; blue copper protein from Alcaligenes faecalis; cupredoxin (CPC) from Cucumis sativus (Cucumber) peelings [PMID: 1468551]; cusacyanin (basic blue protein; plantacyanin, CBP) from cucumber; halocyanin from Natronomonas pharaonis (Natronobacterium pharaonis) [PMID: 8195126], a membrane associated copper-binding protein; pseudoazurin from Pseudomonas; rusticyanin from Thiobacillus ferrooxidans [PMID: 1879547]; stellacyanin from Rhus vernicifera (Japanese lacquer tree); umecyanin from the roots of Armoracia rusticana (Horseradish); and allergen Ra3 from ragweed. This pollen protein is evolutionary related to the above proteins, but seems to have lost the ability to bind copper.

Although there is an appreciable amount of divergence in the sequences of all these proteins, the copper ligand sites are conserved. This entry represents a conserved site that includes two of the ligands: a cysteine and a histidine.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns