1. Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131
2. Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, Wisconsin 53706-1544
3. School of Biology and Biochemistry and Questor Centre, The Queen's University of Belfast, Medical Biology Centre, 97, Lisburn Road, BT9 7BL Belfast, Northern Ireland
4. Molecular Structure Unit, Laboratory of Neurotoxicology, NIMH Building 10, Room 3N309, 10 Center Drive, MSC 1262 Bethesda, Maryland 20892-1262