The Crystal Structure of Cobalt-Substituted Pseudoazurin from Alcaligenes faecalis

作者：Gessmann Renate; Kyvelidou Christiana; Papadovasilaki Maria; Petratos Kyriacos^*

来源：Biopolymers, 2011, 95(3): 202-207.

DOI：10.1002/bip.21553

• blue-copper protein
• pseudoazurin
• metal substitution
• Co(II)-derivative
• crystal structure
• Alcaligenes faecalis

The Cu(II) center at the active site of the blue copper protein pseudoazurin from Alcaligenes faecalis has been substituted by Co(II) via denaturing of the protein, chelation and removal of copper by EDTA and refolding of the apo-protein, followed by addition of an aqueous solution of CoCl2. Sitting drop vapour diffusion experiments produced green hexagonal crystals, which belong to space group P6(5), with unit cell dimensions a = b = 50.03, c = 98.80 angstrom. Diffraction data, collected at 291 K on a copper rotating anode X-ray source, were phased by the anomalous signal of the cobalt atom. The structure was built automatically, fitted manually and subsequently refined to 1.86 angstrom resolution. The Co-substituted protein exhibits similar overall geometry to the native structure with copper. Cobalt binds more strongly to the axial Met86-S delta, and retains the tetrahedral arrangement with the four ligand atoms, His40-N delta(I), Cys78-S gamma, His81-N delta(I) and 86Met-S delta, although the structure is less distorted than the native copper protein. The structure reported herein, is the first crystallographic structure of a Co(II)-substituted pseudoazurin.

• 出版日期2011-3