1. Novartis Institute for Tropical Diseases, 10 Biopolis Road, no. 05-01, Chromos, Singapore 138670, Singapore
2. Department of Biochemistry & Molecular Biology, Department of Phamarcology & Toxicology, Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555, United States