1 Core Facility Protein Analysis, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117, Berlin, Germany. Electronic address: jungblut@mpiib-berlin.mpg.de.
2 University of Oslo, Department of Biosciences, P.O. Box 1066, Blindern, 0316 Oslo, Norway. Electronic address: bernd.thiede@ibv.uio.no.
3 Mass Spectrometric Proteomics Institute for Clinical Chemistry & Laboratory Medicine, Campus Forschung, N27 Raum 00.008, University Medical Center Hamburg-Eppendorf Martinistr. 52, 20246, Hamburg,Germany. Electronic address: hschluet@uke.de.