1. Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A
0B8, Canada
2. Chemistry
Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
3. Joint
BSC-CRG-IRB Programme on Computational Biology, Institute for Research in Biomedicine, Baldiri i Reixac 19, 08028 Barcelona, Spain
4. Departament
de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Avgda Diagonal 643, 08028 Barcelona, Spain