1. Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA.
2. NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
3. Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
4. NIST Center for Neutron Research, Gaithersburg, MD 20878, USA.
5. Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
6. Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
7. Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.