1Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
2Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
3Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
4Netherlands Proteomics Centre Padualaan 8, 3584CH, Utrecht, The Netherlands