Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.|Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.|Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.|Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.