1. Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
2. Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
3. Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
4. Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Mail Code HRC3, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States