1. Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, United States
2. Center for Drug Discovery, Baylor College of Medicine, Houston, Texas 77030, United States
3. Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas 77030, United States
4. Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030, United States
5. Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States