1. Contribution from the Departments of Biochemistry and Physics and Center for Structural Biology, Vanderbilt University, 5140 BIOSCI/MRB III, Nashville, Tennessee 37232-8725; Department of Molecular Biology (MB-9), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037; Department of Biochemistry, Cellular and Molecular Biology, and Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Tennessee 37996; and Life Sciences Division, Oak...