Investigating the Effect of Crystallization Conditions on the Validity of Phycocyanin Structural Details

Abstract

A high resolution (1.43 A) crystal structure of phycocyanin from the thermophillic cyanobacteria T. vulcanus has been solved with crystallization conditions varying from those previously reported for this species (PDB code 1KTP, 1.6 A). The new crystal structure is isomorphous to the previous one and since both structures are of high resolution this provides an ideal model for investigating the pure effects of solvent on the crystal structure independent of crystal packing effects. The effect of the crystallization conditions on the conformation of individual amino acid side chains and the cofactor environment is discussed.