scholarly journals Electro-Steric Mechanism of CLC-2 Chloride Channel Activation

2020 ◽  
Author(s):  
José J. De Jesús-Pérez ◽  
G. Arlette Méndez-Maldonado ◽  
Irma L. Gonzalez-Hernandez ◽  
Victor De la Rosa ◽  
Roberto Gastélum-Garibaldi ◽  
...  
Keyword(s):  
Chloride Channels ◽  
Homology Modelling ◽  
Activation Mechanism ◽  
Molecular Dynamic Simulations ◽  
Steric Repulsion ◽  
Dynamic Simulations ◽  
Channel Activation ◽  
Voltage Gated ◽  
Functional Studies ◽  
Muscle Excitability

AbstractTwo-pore voltage-gated CLC chloride channels control neuronal and muscle excitability. They share a dimeric structure but their activation mechanism remains unresolved. Here we determine the step-by-step activation mechanism of the broadly expressed CLC-2 channel using homology modelling, molecular dynamic simulations and functional studies. We establish that a two-leaf gate formed by Tyr561-H2O-Glu213 flanked by Lys568/Glu174 and Lys212 closes the canonical pore. Activation begins when a hyperpolarization-propelled intracellular chloride occupies the pore and splits Tyr561-H2O-Glu213 by electrostatic/steric repulsion. Unrestrained Glu213 rotates outwardly to bind Lys212 but the pore remains closed. Protonation breaks the Glu213-Lys212 interaction while another chloride occupies the pore thus catalysing chloride exit via Lys212. Also, we found that the canonical pore is uncoupled from a cytosolic cavity by a Tyr561-containing hydrophobic gate that prevents Glu213 protonation by intracellular protons. Our data provide atomistic details about CLC-2 activation but this mechanism might be common to other CLC channels.

scholarly journals Transduction of Voltage and Ca2+ Signals by Slo1 BK Channels

Physiology ◽  
2013 ◽  
Vol 28 (3) ◽  
pp. 172-189 ◽  
Author(s):  
T. Hoshi ◽  
A. Pantazis ◽  
R. Olcese
Keyword(s):  
Gate Voltage ◽  
Bk Channels ◽  
Activation Mechanism ◽  
Channel Activation ◽  
Regulatory Factors ◽  
Voltage Sensors ◽  
Voltage Gated ◽  
Intracellular Ca ◽  
Biophysical Mechanism ◽  
Allosteric Model

Large-conductance Ca2+- and voltage-gated K+ channels are activated by an increase in intracellular Ca2+ concentration and/or depolarization. The channel activation mechanism is well described by an allosteric model encompassing the gate, voltage sensors, and Ca2+ sensors, and the model is an excellent framework to understand the influences of auxiliary β and γ subunits and regulatory factors such as Mg2+. Recent advances permit elucidation of structural correlates of the biophysical mechanism.

scholarly journals Ranking the Efficiency of Gas Hydrate Anti-agglomerants through Molecular Dynamic Simulations

2021 ◽  
Vol 125 (5) ◽  
pp. 1487-1502
Author(s):  
Stephan Mohr ◽  
Felix Hoevelmann ◽  
Jonathan Wylde ◽  
Natascha Schelero ◽  
Juan Sarria ◽  
...  
Keyword(s):  
Molecular Dynamic ◽  
Gas Hydrate ◽  
Molecular Dynamic Simulations ◽  
Dynamic Simulations

scholarly journals Flow of long chain hydrocarbons through carbon nanotubes (CNTs)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pranay Asai ◽  
Palash Panja ◽  
Raul Velasco ◽  
Milind Deo
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamic ◽  
Continuum Models ◽  
Molecular Dynamic Simulations ◽  
Dynamic Simulations ◽  
Pharmaceutical Applications ◽  
Molecular Sizes ◽  
Hydrocarbon Molecules ◽  
Pressure Driven Flow ◽  
Long Chain

AbstractThe pressure-driven flow of long-chain hydrocarbons in nanosized pores is important in energy, environmental, biological, and pharmaceutical applications. This paper examines the flow of hexane, heptane, and decane in carbon nanotubes (CNTs) of pore diameters 1–8 nm using molecular dynamic simulations. Enhancement of water flow in CNTs in comparison to rates predicted by continuum models has been well established in the literature. Our work was intended to observe if molecular dynamic simulations of hydrocarbon flow in CNTs produced similar enhancements. We used the OPLS-AA force field to simulate the hydrocarbons and the CNTs. Our simulations predicted the bulk densities of the hydrocarbons to be within 3% of the literature values. Molecular sizes and shapes of the hydrocarbon molecules compared to the pore size create interesting density patterns for smaller sized CNTs. We observed moderate flow enhancements for all the hydrocarbons (1–100) flowing through small-sized CNTs. For very small CNTs the larger hydrocarbons were forced to flow in a cork-screw fashion. As a result of this flow orientation, the larger molecules flowed as effectively (similar enhancements) as the smaller hydrocarbons.

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