1. Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
2. Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute for Science and Technology (BIST), 08028 Barcelona, Spain
3. Joint BSC-CRG-IRB Research Program in Computational Biology, 08028 Barcelona, Spain
4. Department of Biochemistry and Biomedicine, University of Barcelona, 08028 Barcelona, Spain