1. Department
of Chemical Physiology, The Scripps Research Institute, 10550 North
Torrey Pines Road, La Jolla, California 92037, United States
2. Molecular
and Cell Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
3. Sciex Separations, 250
South Kraemer Boulevard, Brea, California 92821, United States
4. Department
of Biochemistry, University of Washington, Seattle, Washington 98195, United States