1. Department of Biochemistry; Vanderbilt University; School of Medicine; 868A Robinson Research Building Nashville TN 37232 USA
2. Department of Chemistry; Vanderbilt University; College of Arts & Science; Station B Box 1822 Nashville TN 37235 USA
3. Department of Chemistry; University of Connecticut; 55 North Eagleville Rd Storrs CT 06269 USA
4. Department of Chemistry and Biochemistry; Ohio State University; 484 West 12th Avenue Columbus OH 43210 USA