1. Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, 9600 Gudelsky Drive, Rockville, Maryland 20850, Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Illinois Institute of Technology, Chicago, Illinois 60616, and Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439