1. Membrane Protein Research Group, Departments of Oncology and Physiology, University of Alberta, and Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada, Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602-5700, and Astbury Centre for Structural Molecular Biology, Institute for Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, United Kingdom