| Primary Identifier | IPR003245 | Type | Domain |
| Short Name | Phytocyanin_dom |
| description | Among the blue copper proteins with a single type I (or "blue") mononuclearcopper site, the plant-specific phytocyanins constitute a distinct subfamilythat can be further subdivided into the families of uclacyanins, stellacyanins,plantacyanins, and early nodulins. Stellacyanins have a blue coppercoordinated by two His, one Cys and one Gln. In plantacyanins and uclacyanins,the ligands of the type-I Cu sites are two His, one Cys and one Met [, , , ]. Early nodulins lack amino acid residues that coordinate Cu, so they are believed to be involved in unknown processes without binding Cu []. Phytocyanins are found in chloropasts of higher plants.The phytocyanin domain has a core of seven polypeptide strands arranged as aβ-sandwich comprising two β-sheets, β-sheet I and β-sheet II. β-sheet I consists of three β-strands and β-sheet IIconsists of four β-strands. A disulfide bridge close the metal centre ischaracteristic for phytocyanins, in contrast to azurins, pseudoazurins, andplastocyanins, where a disulfide bond is located on the distal side of theβ-barrel. This disuldide bridge may play a crucial role in maintaining thetertiary structure of the protein and/or the formation of the copper bindingcentre because one of the His ligands of copper is followed directly by abridging Cys residue [, , , ]. Some members of this family (P93328) may not bind copper due to the lack of key residues. Some proteins known to contain a phytocyanin domain are listed below:Cucumber basic protein (CBP).Spinach basic protein (SBP).Cucumber stellacyanin (CST).Zucchini mavicyanin.Horseradish umecyanin [, ]. Some of the proteins in this family are allergens. The allergens in this family include allergens with the following designations: Amb a 3. |
