1. School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
2. Department
of Biochemistry and
Molecular Biology and Gordon Center for Integrative Science, The University of Chicago, Chicago, Illinois 60637,
United States
3. Beckman Institute, University of Illinois at Urbana−Champaign,
Urbana, Illinois 61801, United States
4. Laboratoire International Associé
Centre National de la Recherche Scientifique - University of Illinois
at Urbana−Champaign,
UMR 7565, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France