1. Department of Biochemistry and Molecular Biology, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Department of Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, Department of Pathobiology, College of Veterinary Science, University of Florida, Gainesville, Florida 32611, and FLOW Inc., Portland, Oregon 97201