ISSN 1063-7745, Crystallography Reports, 2006, Vol. 51, No. 2, pp. 278–285. © Pleiades Publishing, Inc., 2006. Original Russian Text © A.V. Lyashenko, N.E. Zhukhlistova, E.V. Stepanova, K. Schirwiz, Yu.N. Zhukova, O.V. Koroleva, V.S. Lamzin, V.N. Zaœtsev, A.G. Gabdulkhakov, A.M. Mikhaœlov, 2006, published in Kristallografiya, 2006, Vol. 51, No. 2, pp. 305–312. 278 INTRODUCTION The practical interest in enzymes is primarily caused by their catalytic activity and specificity of action. Laccase (oxygen oxidoreductase, EC 1.10.3.2) is an enzyme catalyzing oxidation of different com- pounds, including o,n-diphenols, aminophenols, and polyamines, as well as some inorganic ions and aryl- diamines with corresponding reduction of molecular oxygen to water [1–3]. The uniquely wide substrate specificity (which can be increased using redox media- tors), bioelectrocatalytical properties, high stability, and the use of oxygen as a second substrate, make lac- case promising in analytical applications, organic syn- thesis, and different detoxication systems. Owing to its oxidase activity, laccase is involved in biodegradation of lignins, which is one of the most important biocon- version processes. The absence of a structural database sufficiently complete for establishing the mechanism of the enzyme action, as well as the unknown relationship between structural data and catalytic properties, limits the effec- tive use of laccase in biotechnology. This situation calls for further X-ray diffraction studies, and, therefore, structural functional investigations of laccase as a bio- logical system. In the last 50 years, laccases from different sources have been intensively investigated by biochemical, spectroscopic, and physicochemical methods. Despite the interest in this protein, difficulties with its crystalli- zation and the heterogeneity of its preparations remained for a long time insurmountable obstacles to the complete X-ray diffraction analysis and resolution of laccase structure. Only recently, the structures of the three laccases from fungi, Coprinus cinereus [4, 5], Trametes versicolor [6, 7], and Melanocarpus albomy- STRUCTURE OF MACROMOLECULAR COMPOUNDS Devoted to Boris Konstantinovich Vaœnshteœn A Preliminary X-ray Diffraction Study of the Laccase from Coriolus zonatus in the Native State A. V. Lyashenko*, N. E. Zhukhlistova*, E. V. Stepanova**, K. Schirwiz***, Yu. N. Zhukova*, O. V. Koroleva**, V. S. Lamzin***, V. N. Zaœtsev****, A. G. Gabdulkhakov*, and A. M. Mikhaœlov* * Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskiœ pr. 59, Moscow, 119333 Russia e-mail: amm@ns.crys.ras.ru ** Bach Institute of Biochemistry, Russian Academy of Sciences, Leninskiœ pr. 33, Moscow, 119071 Russia *** European Molecular Biology Laboratory, Hamburg, Germany **** Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, UK Received October 6, 2005 Abstract—The copper-containing enzyme laccase is involved, owing to its oxidase activity, in the biodegrada- tion of lignins—one of the most important bioconversion processes. On the basis of the X-ray diffraction data for the laccase from Coriolus zonatus, the spatial structure of this enzyme is determined with a resolution of 3.2 Å. R and R free are 0.2347 and 0.2976, respectively, and the rms deviations of the bond lengths and the bond angles are 0.009 and 1.547 Å, respectively. The three-domain structure of the laccase from Coriolus zonatus is confirmed, where each domain is represented by a protein from the cupredoxin family. The spatial organization of the active center of the protein is established. The mononuclear center contains a copper ion Cu(1) with the atoms of S_Cys453, ND1_His395 , and ND1_His458 ligands. The trinuclear center is formed by copper ions Cu(2), Cu(3), and Cu(4), surrounded by ligands of eight nitrogen atoms of the histidines of the first and third domains of the protein His66, His109, His454, His111, His400, His452, His64 , and His398 . The Cu(1) ion is located at distances of 11.84 and 13.22 Å from the Cu(2) and Cu(3) ions, respectively. The distance between the Cu(2) and Cu(3) ions is 5.14 Å and the Cu(4)–Cu(2) and Cu(4)–Cu(3) distances are 4.75 and 4.41 Å, respec- tively. PACS numbers: 87.14.Ee DOI: 10.1134/S1063774506020143