1. Protein Engineering Network of Centres of Excellence, University of Alberta, Edmonton, Alberta T6G 2S2, Canada, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada, Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106-4970, Department of Biochemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada, and Department of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada