1. Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208, Institute for Molecular Science, Mydaiji, Okazaki 444-8585, Japan, Department of Biochemistry, Yamagata University School of Medicine, Yamagata 990-23, Japan, Department of Physiology and Biophysics, Case Western University School of Medicine, Cleveland, Ohio 44106-4970, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan