Research Topics - Membrane Biology

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Biological cells are surrounded by a highly versatile, yet very feeble cellular membrane and need to balance differences between the cell's interior and exterior that otherwise would burst the membrane. For example, the osmotic pressures inside and outside the cell need to be closely balanced. Thousands of proteins in the membrane act as gatekeepers, opening pores that can also act as safety valves, helping to reduce the interior-exterior difference in pressure rapidly. One such protein, the mechanosensitive channel of small conductance MscS (see the Mar 2008 highlight, "Observation and Simulation Depict Cell's Safety Valve", the Feb 2007 highlight, "Observing and Modeling a Crucial Membrane Channel", the May 2006 highlight, "Electrical Safety Valve", and the Nov 2004 highlight, "Japanese Lantern Protein") opens in response to cellular membrane tension generated due to a drastic imbalance in osmotic pressure as it arises when a bacterial cell suddenly finds itself in fresh water, rather than a highly saline physiological medium. The MscS channel widens then to jettison molecules out of the cell and reduce tension on the cellular membrane quickly. In a recent report, researchers have combined experimental data from electron paramagnetic measurements and computer modeling to reveal in atomic detail how MscS opens and closes its channel. Combining measurement and modeling, the researchers established a highly resolving computational microscope, unmatched by existing microscopes (more on our MscS website).

All Spotlights

Papers

Enhanced sampling techniques in molecular dynamics simulations of biological systems. Rafael C. Bernardi, Marcelo C. R. Melo, and Klaus Schulten. Biochimica et Biophysica Acta, 2015. In Press.

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.

Reconciling the roles of kinetic and thermodynamic factors in membrane-protein insertion. James C. Gumbart, Ivan Teo, Benoit Roux, and Klaus Schulten. Journal of the American Chemical Society, 135:2291-2297, 2013.

The p7 protein of hepatitis C virus forms structurally plastic, minimalist ion channels. Danielle E. Chandler, Francois Penin, Klaus Schulten, and Christophe Chipot. PLoS Computational Biology, 8:e1002702, 2012.

Molecular dynamics investigation of the w current in the Kv1.2 voltage sensor domains. Fatemeh Khalili-Araghi, Emad Tajkhorshid, Benoit Roux, and Klaus Schulten. Biophysical Journal, 102:258-267, 2012.