1. J. L. Battiste, H. Mao, J. R. Williamson, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2. N. S. Rao, D. R. Muhandiram, L. E. Kay, Protein Engineering Centers of Excellence and Departments of Medical Genetics, Biochemistry, and Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
3. R. Tan and A. D. Frankel, Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA.