Department of Biochemistry, Stanford University, Stanford, California, United States of America.|Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands, Department of Physics and Center for Nanoscience (CeNS), University of Munich, Munich, Germany.|Department of Biochemistry, Stanford University, Stanford, California, United States of America, Biophysics Program, Stanford University, Stanford, California, United States of America, Department of Physics, Stanford University, Stanford, California, United States of America.