1. Laboratory of Biomolecular Structure and Dynamics, and Department of Inorganic Chemistry, Faculty of Science, Masaryk University, Kotlárská 2, CZ 611 37 Brno, Czech Republic, Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-ku, Tokio 113-8657, Japan, Department of Molecular Biophysics, Center for Chemistry and Chemical Engineering, Lund University, S-221 00 Lund, Sweden, and Structural GenomiX, 10505 Roselle Street, San Diego, California 92121