1. School of Medicine and Biomedical Sciences, The University at Buffalo, Buffalo, New York 14214, Departamento de Química, Centro de Investigación y de Estudios Avanzados (Cinvestav), 07360 México, D.F., Mexico, Department of Chemistry, Biochemistry and Biophysics, Niagara University, Niagara University, New York 14109, Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, and Department of Chemistry, Stanford University, Stanford, California 94305