Computing osmotic permeabilities of aquaporins AQP4, AQP5, and GlpF from near-equilibrium simulations

POSTER

Abstract

Measuring or computing the single-channel permeability of aquaporins/aquaglyceroporins (AQPs) has long been a challenge. We report large scale simulations of osmotic current under sub M gradient through three AQPs (water channels AQP4 and AQP5 and glycerol-water channel GlpF. These simulations were implemented with hybrid periodic boundary conditions devised to avoid the artifactitious mixing across the membrane in a regular PME simulation. The computed single-channel permeabilities at 5~\textdegree C and 25~\textdegree C are in agreement with recently refined experiments on GlpF. The Arrhenius activation energies extracted from our simulations for all the three AQPs agree with the \textit{in vitro} measurements. We observe that AQP4, that is particularly rich in the central nervous system, is more efficient in water conduction and more temperature-sensitive than other water-only channels (excluding glycerol channels that also conduct water when not inhibited by glycerol).

Authors

  • Thierry Wambo

    The University of Texas at San Antonio

  • Qiye Zheng

    Santa Fe Institute, Baylor University, University of Texas at Dallas, Department of Chemistry, The University of Texas at Austin, Jozef Stefan Institute, Texas A&M University-Commerce, Commerce, Texas 75429, Cyclotron Institute, Texas A&M University, College Station, Texas 77843, Texas A&M University, Department of Physics, Texas State University, Department of Physics, Baylor University, University of Texas at El Paso, Univ of Texas, El Paso, University of Science and Technology of China, The University of Texas at Dallas, Faculty, None, Southwestern University, Texas State University, Texas A&M University - Commerce, UT Southwestern Medical Center, National High Magnetic Field Laboratory, The Cyclotron Institute at Texas A&M University, Department of Biological Sciences, Texas State Univ-San Marcos, The University of Texas at Dallas, Richardson, Texas 75080, King Abdullah University of Science and Technology, Univ of Texas, Dallas, N.Chiao Tung U., UT Dallas, Inorganic Chemistry and Catalysis Group, Utrecht University, Electrical & Computer Engineering, Baylor University, Department of Materials Science and NanoEngineering, Rice University, University of Texas at Arlington, University of Chicago, The University of Mississippi, Astronomical Observatory, Warsaw University, Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Rochester Institute of Technology, California Institute of Technology, University of Houston, NASA-GSFC and UMBC, MD, Virginia Tech, VA, Texas Christian University, The University of Texas at San Antonio, Department of Physics, Teivecca Nazarene University, Weatherford College, Air Force Research Laboratory, Sensors Directorate, WPAFB, OH, USA, Air Force Research Laboratory, Directed Energy Directorate, KAFB, NM, US, Department of Physics & Astronomy, University of Texas at San Antonio TX, USA, University of Arizona, University of North Carolina at Chapel Hill, Stanford University, Harvard Center for Astrophysics, Texas A\&M University, UTSW, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, Boston College, Chestnut Hill, Massachusetts 02467, Naval Research Laboratory, Washington, D.C. 20375

  • Qiye Zheng

    Santa Fe Institute, Baylor University, University of Texas at Dallas, Department of Chemistry, The University of Texas at Austin, Jozef Stefan Institute, Texas A&M University-Commerce, Commerce, Texas 75429, Cyclotron Institute, Texas A&M University, College Station, Texas 77843, Texas A&M University, Department of Physics, Texas State University, Department of Physics, Baylor University, University of Texas at El Paso, Univ of Texas, El Paso, University of Science and Technology of China, The University of Texas at Dallas, Faculty, None, Southwestern University, Texas State University, Texas A&M University - Commerce, UT Southwestern Medical Center, National High Magnetic Field Laboratory, The Cyclotron Institute at Texas A&M University, Department of Biological Sciences, Texas State Univ-San Marcos, The University of Texas at Dallas, Richardson, Texas 75080, King Abdullah University of Science and Technology, Univ of Texas, Dallas, N.Chiao Tung U., UT Dallas, Inorganic Chemistry and Catalysis Group, Utrecht University, Electrical & Computer Engineering, Baylor University, Department of Materials Science and NanoEngineering, Rice University, University of Texas at Arlington, University of Chicago, The University of Mississippi, Astronomical Observatory, Warsaw University, Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Rochester Institute of Technology, California Institute of Technology, University of Houston, NASA-GSFC and UMBC, MD, Virginia Tech, VA, Texas Christian University, The University of Texas at San Antonio, Department of Physics, Teivecca Nazarene University, Weatherford College, Air Force Research Laboratory, Sensors Directorate, WPAFB, OH, USA, Air Force Research Laboratory, Directed Energy Directorate, KAFB, NM, US, Department of Physics & Astronomy, University of Texas at San Antonio TX, USA, University of Arizona, University of North Carolina at Chapel Hill, Stanford University, Harvard Center for Astrophysics, Texas A\&M University, UTSW, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, Boston College, Chestnut Hill, Massachusetts 02467, Naval Research Laboratory, Washington, D.C. 20375