1. Department of Biochemistry, University of Wisconsin, 420 Henry Mall, Madison, Wisconsin 53706 (E.H., R.M.A.)
2. Departament de Bioquı́mica i Biologia Molecular, Universitat de València, Dr. Moliner 50, Burjassot, València, E-46100 Spain (H.M., L.P.)
3. Division of Toxicological Sciences, Department of Environmental Health Sciences, Johns Hopkins University School of Public Health, Bethesda, Maryland 20892 (S.-J.L., V.C.C.)