1. Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA.
2. Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA.
3. Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
4. Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA.
5. Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.