Peptides were extracted from the gel slices via sonication in 50 μl 60% acetonitrile/5%TFA, dried via vacuum centrifugation, and reconstituted in 15 μl 0.1% TFA. Tryptic peptides were desalted/enriched using a C18 ZipTip column (Millipore, Billerica, MA) according to manufacturer’s instructions and the eluant was spotted on a MALDI plate and dried. Samples were analyzed using a MALDI-LTQ mass spectrometer (ThermoFinnigan, San Jose, CA). A full MS scan in high-mass range (m/z 600-4000, 5 microscans) was performed. The 50 most intense peaks in the full MS spectrum were selected, and MSMS scans learn more were performed for those ions in high-mass

range (m/z 50-4000, 5 microscans), the normalized collision energy for MSMS was 35. Xcalibur software was used to process the mass spectrometric data, and the NCBInr database and the Bioworks 3.2 search engine software were used for database searching. Acknowledgements The project described was supported by NIH grant #U54 BAY 11-7082 datasheet AI057157 from Southeastern Regional Center of Excellence for Emerging Infections and Biodefense,

by NIH grants AI074582 and AI079482 (to JEB) and AI061260 (to MAM), and by Department of Defense Army grant W81XHW-05-1-0227. The authors also thank Cory Blackwell and Himangi Jayakar for helpful discussions. We also thank Jyothi Parvathareddy, OTX015 solubility dmso and Janice Collum for their technical assistance. References 1. Hoel T, Scheel O, Nordahl SH, Sandvik T: Water- and airborne Francisella tularensis biovar palaearctica isolated from human blood. Infection 1991,19(5):348–350.PubMedCrossRef 2. Siret V, Barataud D, Prat M, Vaillant V, Ansart S, Le Coustumier A, Vaissaire J, Raffi F, Garre M, Capek I: An outbreak of airborne tularaemia in France, August

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