1. Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
2. Center for Structural Genomics of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
3. Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA.
4. National Cancer Institute-RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Frederick, MD 21702, USA.
5. Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
6. Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.