Search results for "KcsA potassium channel"

showing 3 items of 3 documents

Kinetic modeling of ion conduction in KcsA potassium channel.

2005

KcsA constitutes a potassium channel of known structure that shows both high conduction rates and selectivity among monovalent cations. A kinetic model for ion conduction through this channel that assumes rapid ion transport within the filter has recently been presented by Nelson. In a recent, brief communication, we used the model to provide preliminary explanations to the experimental current-voltage J-V and conductance-concentration g-S curves obtained for a series of monovalent ions (K(+),Tl(+), and Rb(+)). We did not assume rapid ion transport in the calculations, since ion transport within the selectivity filter could be rate limiting for ions other than native K(+). This previous wor…

ChemistrySodiumPositive IonsIonic ConductivityAnalytical chemistryKcsA potassium channelUNESCO::FÍSICAGeneral Physics and AstronomyConductanceIon-associationRubidiumIonReaction rate constant:FÍSICA [UNESCO]Biomembrane TransportPotassium ; Thallium ; Rubidium ; Sodium ; Positive Ions ; Ionic Conductivity ; Biomembrane TransportPotassiumIonic conductivityPhysical and Theoretical ChemistryThalliumIon transporterIon channelThe Journal of chemical physics
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Ion conduction in the KcsA potassium channel analyzed with a minimal kinetic model.

2004

We use a model by Nelson to study the current-voltage and conductance-concentration curves of bacterial potassium channel KcsA without assuming rapid ion translocation. Ion association to the channel filter is rate controlling at low concentrations, but dissociation and transport in the filter can limit conduction at high concentration for ions other than ${\mathrm{K}}^{+}$. The absolute values of the effective rate constants are tentative but the relative changes in these constants needed to qualitatively explain the experiments should be of significance.

Materials scienceIon TransportPotassium ChannelsCell MembraneKcsA potassium channelElectric ConductivityThermodynamicsIon-associationThermal conductionModels BiologicalPotassium channelDissociation (chemistry)IonMembrane PotentialsKineticsReaction rate constantBacterial ProteinsModels ChemicalPotassiumPhysical chemistryComputer SimulationIon Channel GatingIon channelPhysical review. E, Statistical, nonlinear, and soft matter physics
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Ion transport through membranes: A computer experiment

1983

Abstract Gramicidin-A is a linear pentadecapeptide antibiotic, which forms transmembrane channels; these have a number of interesting conductance characteristics [1, 2 and Refs. therein], as for example high specific ion fluxes (a single channel carries about 10 7 sodium ions/sec at 25 °C, 1 M NaCl and 100 mV transmembrane d.d.p.) have a remarkable ion selectivity among the monovalent cations. The permeability ratios with respect to sodium were found to be in following order H + (150) > NH 4 + (8.9) > Cs + (5.8) > Rb + (5.5) > K + (3.9) > Na + (1.0) > Li + (0.33). The channel is impermeable to anions and to divalent cations and it exhibits saturation and maxima in conductance as a function …

chemistry.chemical_classificationTransmembrane channelsAnalytical chemistryKcsA potassium channelConductanceIon Transport ProcessIonDivalentInorganic Chemistrychemistry.chemical_compoundCrystallographychemistryMaterials ChemistryGramicidinPhysical and Theoretical ChemistryIon transporterInorganica Chimica Acta
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