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Contribution of ion binding affinity to ion selectivity and permeation in KcsA, a model potassium channel

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dc.contributor.authorRenart Pérez, María Lourdes
dc.contributor.authorMontoya Díaz, Estefanía
dc.contributor.authorFernández Carvajal, Asia María
dc.contributor.authorMolina Gallego, María Luisa
dc.contributor.authorPoveda Larrosa, José Antonio
dc.contributor.authorEncinar Hidalgo, José Antonio
dc.contributor.authorAyala Torres, Antonio Vicente
dc.contributor.authorGómez Pérez, Francisco Javier
dc.contributor.authorMorales Calderón, Andrés
dc.contributor.authorGonzález Ros, José Manuel
dc.contributor.departmentBioquímica y Biología Molecular B e Inmunología
dc.date.accessioned2024-07-04T11:22:37Z
dc.date.available2024-07-04T11:22:37Z
dc.date.issued2012-04-17
dc.description© 2012 American Chemical Society. This document is the Published version of a Published Work that appeared in final form in Biochemistry. To access the final edited and published work see https://doi.org//10.1021/bi201497n
dc.description.abstractIon permeation and selectivity, key features in ion channel function, are believed to arise from a complex ensemble of energetic and kinetic variables. Here we evaluate the contribution of pore cation binding to ion permeation and selectivity features of KcsA, a model potassium channel. For this, we used E71A and M96V KcsA mutants in which the equilibrium between conductive and nonconductive conformations of the channel is differently shifted. E71A KcsA is a noninactivating channel mutant. Binding of K+ to this mutant reveals a single set of low-affinity K+ binding sites, similar to that seen in the binding of K+ to wild-type KcsA that produces a conductive, low-affinity complex. This seems consistent with the observed K+ permeation in E71A. Nonetheless, the E71A mutant retains K+ selectivity, which cannot be explained on the basis of just its low affinity for this ion. At variance, M96V KcsA is a rapidly inactivating mutant that has lost selectivity for K+ and also conducts Na+. Here, low-affinity binding and high-affinity binding of both cations are detected, seemingly in agreement with both being permeating species in this mutant channel. In conclusion, binding of the ion to the channel protein seemingly explains certain gating, ion selectivity, and permeation properties. Ion binding stabilizes greatly the channel and, depending upon ion type and concentration, leads to different conformations and ion binding affinities. High-affinity states guarantee binding of specific ions and mediate ion selectivity but are nonconductive. Conversely, low-affinity states would not discriminate well among different ions but allow permeation to occur.es
dc.embargo.termsSi
dc.formatapplication/pdfes
dc.format.extent10es
dc.identifier.doihttps://doi.org/10.1021/bi201497n
dc.identifier.eisbnBiochemistry 2012, 51, 18, 3891–3900es
dc.identifier.issnPrint: 0006-2960
dc.identifier.issnElectronic: 1520-4995
dc.identifier.urihttp://hdl.handle.net/10201/142857
dc.languageenges
dc.relationSupported by grants from the Spanish DGI (BFU2008-0062/ BMC, BFU2009-08346, and BFU2011-25920) and Consolider-Ingenio (2010 CSD2-2008-00005) and from the Generalitat Valenciana Prometeo (2010/046)es
dc.relation.publisherversionhttps://pubs.acs.org/doi/10.1021/bi201497n
dc.rightsinfo:eu-repo/semantics/embargoedAccesses
dc.subjectIonses
dc.subjectPeptides and proteinses
dc.subjectPotassiumes
dc.subjectScreening assayses
dc.subjectSelectivityes
dc.titleContribution of ion binding affinity to ion selectivity and permeation in KcsA, a model potassium channeles
dc.typeinfo:eu-repo/semantics/articlees
dspace.entity.typePublicationes
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