Crystal structure of auracyanin, a "blue" copper protein from the green thermophilic photosynthetic bacterium Chloroflexus aurantiacus

Abstract

Auracyanin B, one of two similar blue copper proteins produced by the thermophilic green non-sulfur photosynthetic bacterium Chloroflexus aurantiacus, crystallizes in space group P6422 (a = b = 115.7 Å, c = 54.6 Å). The structure was solved using multiple wavelength anomalous dispersion data recorded about the CuK absorption edge, and was refined at 1.55 Å resolution. The molecular model comprises 139 amino acid residues, one Cu, 247 H2O molecules, one Cl- and two SO42-. The final residual and estimated standard uncertainties are R = 0.198, ESU = 0.076 Å for atomic coordinates and ESU = 0.05 Å for Cu - ligand bond lengths, respectively. The auracyanin B molecule has a standard cupredoxin fol..