1. Chemical, Physical, Structural Biology Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
2. Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030, USA
3. Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
4. Department of Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA