1. Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400
2. Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, New York 10065
3. Graduate Program in Biochemistry and Structural Biology, and Graduate Program in Biophysics, State University of New York at Stony Brook, Stony Brook, New York 11794