1. Contribution from the Centre especial de Recerca en Química Teòrica, Parc Científic de Barcelona, Josep Samitier 1-5, 08028 Barcelona, Spain, Institute of Crystallography of Russian Academy of Sciences, Lenisky Prospekt 59, 119333 Moscow, Russia, Institut de Biologia Molecular de Barcelona-CSIC and Institut de Recerca Biomèdica, Parc Científic de Barcelona, Josep Samitier 1-5, 08028 Barcelona, Spain, Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW,...