1. Scuola Normale Superiore, Piazza dei Cavalieri, I-56126 Pisa, Italy, Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, I-40126 Bologna, Italy, Unit of Drug Discovery and Development, Italian Institute of Technology, Via Morego 30, I-16163 Genoa, Italy, and Computational Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, USI Campus, Via Giuseppe Buffi 13, CH-6900 Lugano, Switzerland