1. Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588, United States
2. Native Mass Spectrometry Guided Structural Biology Center, Ohio State University, Columbus, Ohio 43210, United States
3. Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210, United States
4. Center for Vaccine Innovation, La Jolla Institute for Immunology, La Jolla, California 92037, United States
5. Department of Medicine, University of California San Diego, La Jolla, California 92037, United States