1. Laboratory of Structural Biology,
National Institute of Environmental Health Sciences, National Institutes of Health, P.O. Box 12233, Research
Triangle Park, North Carolina 27709-12233, United States
2. Penn State University, 320
Steidle PSU, University Park, Pennsylvania 16802, United States
3. Department of Chemistry, CB3290, University of North Carolina at Chapel Hill, Chapel
Hill, North Carolina 27599, United States