1. Mass Spectrometry Laboratory, MolSys Research Unit, Department of Chemistry, University of Liège, Allée du Six Août, 11, Quartier Agora, Liège 4000, Belgium
2. Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
3. Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla 92093-0657, California, United States