1. Structural Biology Center, Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
2. California Institute of Neuroscience, Thousand Oaks, California 91360, United States
3. National Skull Base Center, Thousand Oaks, California 91360, United States
4. Department of Biochemistry and Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada
5. Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
6. Department of Neurosurgery, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama 36617 United States