1. Department of Internal Medicine, University of Texas Medical Branch , Galveston , TX 77555 , USA
2. Life Sciences Division, Lawrence Berkeley National Laboratory , Berkeley , CA 94720 , USA
3. Purdue Proteomics Facility, Bindley Bioscience Center, Purdue University , IN 47907 , USA
4. Department of Microbiology and Immunology, University of Texas Medical Branch , Galveston , TX 77555 , USA