1. Molecular
Biophysics Laboratory, Photonics Center, and Department of Physics, Boston University, Boston, Massachusetts 02215, United States
2. Center
for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas 77030, United States
3. Department
of Biophysical Organic Chemistry, Leiden Institute of Chemistry, Leiden University, 2300 AR Leiden, The Netherlands