Three-dimensional structure of a recombinant peroxidase from Coprinus cinereus at 2.6 A resolution.

The structure of a recombinant peroxidase from the ink cap, Coprinus cinereus, CiP, is reported to 2.6 A resolution and refined to a R-value of 18.1%. The structure was solved by molecular replacement using the coordinates from a newly published ligninase structure. LiP. CiP crystallizes in space group P2(1)2(1)2(1) with two independent molecules in the asymmetric unit related by the vector 0.29b + 0.5c. The two CiP molecules are structurally identical; each contains two Ca2+ ions in positions equivalent to those found in the LiP structure. Two N-acetylglucosamines and one mannose residue were fitted into the density adjacent to two of the three predicted glycosylation sites. The refinement also included 40 and 41 water molecules, respectively, in the two CiP molecules. The structure of CiP displays a folding very similar to that of LiP. The active sites are almost identical in the LiP and CiP structures. CiP has a much larger opening to the active site than LiP.