Fig. 2.

Structure of phycocyanin from Spirulina platensis. (A) Three-dimensional structure of phycocyanin from cyanobacterium S. platensis in form of hexamer, image from PDB (https://www.rcsb.org/structure/1GH0). (B) Phycocyanin exists as (αβ)6 hexamer and both chains have the α-helix structure. (Green, brown and pink represent α subunit. Grey, yellow and dark brown represent β subunit). (C) (D) Three-dimensional and secondary structure of phycocyanobilin. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)