Phytocyanins uclacyanin

The third class consists of proteins that are composed of one or more BCB domains fused to a sequence domain(s) characteristic of evolutionarily unrelated protein families. Such a mosaic domain organization has been found in the phytocyanin protein family, stellacyanins, uclacyanins, and the recently characterized dicyanins (Section V) in blood coagulation factor VIII (Section VIII) and in nitrous oxide reductase (Section IX). 

It is also important to note that plants house a large group of phytocyanin-related proteins (22 and 24 in Arabidopsis and rice, respectively) that have extensive sequence identity and identical domain architecture to the stellacyanins and uclacyanins but lack the copper-hgating amino acid residues that are crucial for the formation of the type 1 copper site. These copper-free proteins, known as early noduhns, share a common ancestor with metazoan ephrins, which are involved in multiple aspects of embryonal development." " ... 

Nersissian AM, Immoos C, Hill MG, Hart PJ, Williams G, Herrmann RG, Valentine JS (1998) Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of phytocyanins plant-specific mononuclear blue copper proteins. Protein Sci 7 1915-1929... 

Phytocyanins are a family of blue copper proteins found exclusively in plants.They are further classified into three subfamilies plantacyanins (PNC), stellacyanins (STC), and uclacya-nins (UCC)." Spectroscopic properties of uclacyanins are closer to those of blue copper centers and thus they were covered in Section 8.4.2.3. The function of phytocyanins has not been determined conclusively. 

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