Por favor, use este identificador para citar o enlazar este ítem:
https://doi.org/10.1021/bi201497n
![](/digitum/image/email_logo.png)
![](/digitum/image/logo-facebook.png)
Título: | Contribution of ion binding affinity to ion selectivity and permeation in KcsA, a model potassium channel |
Fecha de publicación: | 17-abr-2012 |
Cita bibliográfica: | Biochemistry 2012, 51, 18, 3891–3900 |
ISSN: | Print: 0006-2960 Electronic: 1520-4995 |
Palabras clave: | Ions Peptides and proteins Potassium Screening assays Selectivity |
Resumen: | Ion 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. |
Autor/es principal/es: | Renart Pérez, María Lourdes Montoya Díaz, Estefanía Fernández Carvajal, Asia María Molina Gallego, María Luisa Poveda Larrosa, José Antonio Encinar Hidalgo, José Antonio Ayala Torres, Antonio Vicente Gómez Pérez, Francisco Javier Morales Calderón, Andrés González Ros, José Manuel |
Facultad/Departamentos/Servicios: | Facultades, Departamentos, Servicios y Escuelas::Departamentos de la UMU::Bioquímica y Biología Molecular "B" e Inmunología |
Versión del editor: | https://pubs.acs.org/doi/10.1021/bi201497n |
URI: | http://hdl.handle.net/10201/142857 |
DOI: | https://doi.org/10.1021/bi201497n |
Tipo de documento: | info:eu-repo/semantics/article |
Número páginas / Extensión: | 10 |
Derechos: | info:eu-repo/semantics/embargoedAccess |
Descripción: | © 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 |
Aparece en las colecciones: | Artículos: Bioquímica y Biología Molecular "B" e Inmunología |
Ficheros en este ítem:
Fichero | Descripción | Tamaño | Formato | |
---|---|---|---|---|
renart-et-al-2012-contribution-of-ion-binding-affinity-to-ion-selectivity-and-permeation-in-kcsa-a-model-potassium.pdf | 1,78 MB | Adobe PDF | ![]() Visualizar/Abrir Solicitar una copia |
Los ítems de Digitum están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.