1. Center
for Theoretical Biological Physics, Rice University, 6100 Main
St., Houston, Texas 77005-1892, United States
2. Department
of Bioengineering, Rice University, 6100 Main St., Houston, Texas 77005-1892, United States
3. Department
of Physics and Astronomy, Rice University, 6100 Main St., Houston, Texas 77005-1892, United States
4. Department
of Chemistry, Rice University, 6100 Main St., Houston, Texas 77005-1892, United States
5. Department
of Biosciences, Rice University, 6100 Main St., Houston, Texas 77005-1892, United States