1. Department of Physics University of California at San Diego La Jolla CA USA
2. Department of Integrative Structural and Computational Biology The Skaggs Institute for Chemical Biology The Scripps Research Institute La Jolla CA USA
3. Department of Chemistry The Skaggs Institute for Chemical Biology The Scripps Research Institute La Jolla CA USA
4. Section of Molecular Biology Division of Biological Sciences University of California at San Diego La Jolla CA USA