1. Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
2. Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, USA
3. Department of Microbial Pathogenesis, Yale University, School of Medicine, New Haven, Connecticut, USA
4. Microbial Sciences Institute, Yale University, School of Medicine, New Haven, Connecticut, USA
5. Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, Buffalo, New York, USA