1. Departments of 1Biological Structure, University of Washington, Seattle, Washington 98195;
2. Departments of 2Biochemistry, University of Washington, Seattle, Washington 98195;
3. Departments of 3Ophthalmology, University of Washington, Seattle, Washington 98195;
4. Departments of 4Chemistry, University of Washington, Seattle, Washington 98195;
5. Departments of 5Pharmacology, and University of Washington, Seattle, Washington 98195;