1. National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Laboratory of Structural Biology, 111 TW Alexander Drive, 27709, Research Triangle Park, NC, USA
2. New York Veterans Affairs Medical Center and Department of Pathology, New York University School of Medicine, New York, New York, USA
3. Blood Systems Research Institute and Departments of Laboratory Medicine and Medicine, University of California-San Francisco, San Francisco, California, USA