3-DIMENSIONAL STRUCTURE OF A RECOMBINANT PEROXIDASE FROM COPRINUS-CINEREUS AT 2.6 ANGSTROM RESOLUTION

The structure of a recombinant peroxidase from the ink cap, Coprinus c inereus, CiP, is reported to 2.6 Angstrom resolution and refined to a R-value of 18.1%. The structure was solved by molecular replacement us ing the coordinates from a newly published ligninase structure, LiP. C iP crystallizes in space group P2(1)2(1)2(1) with two independent mole cules in the asymmetric unit related by the vector 0.29 $$($) over bar b + 0.5 $$($) over bar c. The two CiP molecules are structurally iden tical; each contains two Ca2+ ions in positions equivalent to those fo und in the LiP structure. Two N-acetylglucosamines and one mannose res idue were fitted into the density adjacent to two of the three predict ed glycosylation sites. The refinement also included 40 and 41 water m olecules, 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.