Research Topics - Membrane Biology
Spotlight - Protein Nanopore
Electrostatic potential map of alpha-hemolysin

image size: 112.7KB

In a biological cell, membrane channels act like miniature valves regulating the flow of ions and other solutes between intracellular compartments and across the cell's boundary. Assembled in complex circuits, they generate, transmit, and amplify signals orchestrating cell function. To investigate how membrane channels work, life scientists, using an extremely fine pipette, isolate a tiny patch of a cell membrane and, in so-called patch clamp measurements, determine electric currents in response to applied electric potentials. Dramatic increase in computational power and its efficient utilization by NAMD allows one today to reproduce such studies computationally, calculating the permeability of a membrane channel to ions and water directly from its atomic structure. In what is one of the largest molecular dynamics simulation to date, described in a recent paper as well as on our web site (here), one copy of the membrane channel alpha-hemolysin, submerged in a lipid membrane and water, was subject to an external electric field that drove ions and water through the channel. The calculations produced also an image of the electrostatic potential across the channel (see figure).

All Spotlights

Papers

Elucidation of lipid binding sites on lung surfactant protein A using X-ray crystallography, mutagenesis and molecular dynamics simulations. Boon Chong Goh, Huixing Wu, Michael J. Rynkiewicz, Klaus Schulten, Barbara A. Seaton, and Francis X. McCormack. Biochemistry, 55:3692-3701, 2016.

The water permeability and pore entrance structure of aquaporin-4 channels depend on lipid bilayer thickness. Jihong Tong, Zhe Wu, Margaret M. Briggs, Klaus Schulten, and Thomas J. Mclntosh. Biophysical Journal, 111:90-99, 2016.

Structural refinement of proteins by restrained molecular dynamics simulations with non-interacting molecular fragments. Rong Shen, Wei Han, Giacomo Fiorin, Shahidul M. Islam, Klaus Schulten, and Benoit Roux. PLoS Computational Biology, 11:e1004368, 2015. (19 pages).

Enhanced sampling techniques in molecular dynamics simulations of biological systems. Rafael C. Bernardi, Marcelo C. R. Melo, and Klaus Schulten. Biochimica et Biophysica Acta, 1850:872-877, 2015.

A highly tilted membrane configuration for the pre-fusion state of synaptobrevin. Andrew E. Blanchard, Mark J. Arcario, Klaus Schulten, and Emad Tajkhorshid. Biophysical Journal, 107:2112-2121, 2014.

Synaptotagmin's role in neurotransmitter release likely involves Ca2+-induced conformational transition. Zhe Wu and Klaus Schulten. Biophysical Journal, 107:1156-1166, 2014.

A structural model of the active ribosome-bound membrane protein insertase YidC. Stephan Wickles, Abhishek Singharoy, Jessica Andreani, Stefan Seemayer, Lukas Bischoff, Otto Berninghausen, Johannes Soeding, Klaus Schulten, Eli van der Sluis, and Roland Beckmann. eLife, 3:e03035, 2014. (17 pages).

Integration of energy and electron transfer processes in the photosynthetic membrane of Rhodobacter sphaeroides. Michaël L. Cartron, John D. Olsen, Melih Sener, Philip J. Jackson, Amanda A. Brindley, Pu Qian, Mark J. Dickman, Graham J. Leggett, Klaus Schulten, and C. Neil Hunter. Biochimica et Biophysica Acta - Bioenergetics, 1837:1769-1780, 2014.

Structural mechanism of voltage-dependent gating in an isolated voltage-sensing domain. Qufei Li, Sherry Wanderling, Marcin Paduch, David Medovoy, Abhishek Singharoy, Ryan McGreevy, Carlos Villalba-Galea, Raymond E. Hulse, Benoit Roux, Klaus Schulten, Anthony Kossiakoff, and Eduardo Perozo. Nature Structural & Molecular Biology, 21:244-252, 2014.

The mechanism of ubihydroquinone oxidation at the Qo-site of the cytochrome bc1 complex. Antony R. Crofts, Sangjin Hong, Charles Wilson, Rodney Burton, Doreen Victoria, Chris Harrison, and Klaus Schulten. Biochimica et Biophysica Acta, 1827:1362-1377, 2013.