1. Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, 540 East Canfield Street, Detroit, Michigan 48201, Department of Microbiology, Institute of Biology Bucharest, 060031 Bucharest, Romania, Life Sciences Collaborative Access Team, Northwestern University Center for Synchrotron Research, Argonne, Illinois 60439, and Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197