1. J. R. Jacobsen, Department of Chemical Engineering, Stanford University, Stanford, CA 94305–5025, USA.
2. C. R. Hutchinson, School of Pharmacy and Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA.
3. D. E. Cane, Department of Chemistry, Box H, Brown University, Providence, RI 02912, USA.
4. C. Khosla, Departments of Chemical Engineering, Chemistry, and Biochemistry, Stanford University, Stanford, CA 94305–5025, USA.