1. Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
2. Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
3. Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
4. Fabrus Inc. (a division of Sevion Therapeutics), San Diego, CA 92121, USA.