InterPro domain: IPR039391

Phytocyanins are blue copper proteins found in chloropasts of higher plants. They can be further subdivided into uclacyanins, stellacyanins, plantacyanins, and early nodulins. Stellacyanins have a blue copper coordinated 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 [ 1 , 2 , 3 , 4 ]. Early nodulins lack amino acid residues that coordinate Cu, so they are believed to be involved in unknown processes without binding Cu [ 5 ].

1. Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of phytocyanins: plant-specific mononuclear blue copper proteins. Protein Sci. 7, 1915-29
2. Crystal structure of plantacyanin, a basic blue cupredoxin from spinach. J. Biol. Inorg. Chem. 5, 666-72
3. Structural reorganization of the copper binding site involving Thr15 of mavicyanin from Cucurbita pepo medullosa (zucchini) upon reduction. J. Biochem. 137, 455-61
4. Crystal structures of oxidized and reduced stellacyanin from horseradish roots. J. Am. Chem. Soc. 127, 158-66
5. Genome-wide identification, structure and expression studies, and mutant collection of 22 early nodulin-like protein genes in Arabidopsis. Biosci. Biotechnol. Biochem. 73, 2452-9