Gating Currents in the Hv1 Proton Channel
| Autor: | Victor De La Rosa, Ian Scott Ramsey |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Proton channel Allosteric regulation Protein domain Biophysics Cooperativity Gating Ion Channels Cell Line 03 medical and health sciences Protein Domains Ph gradient Humans Channels and Transporters New and Notable Chemistry Conductance Hydrogen-Ion Concentration Transmembrane protein Kinetics 030104 developmental biology Mutation Thermodynamics Protons Ion Channel Gating |
| Zdroj: | Biophysical Journal. 114:2844-2854 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/j.bpj.2018.04.049 |
| Popis: | The Hv1 proton channel shares striking structural homology with fourth transmembrane helical segment-type voltage-sensor (VS) domains but manifests distinctive functional properties, including a proton-selective “aqueous” conductance and allosteric control of voltage-dependent gating by changes in the transmembrane pH gradient. The mechanisms responsible for Hv1’s functional properties remain poorly understood, in part because methods for measuring gating currents that directly report VS activation have not yet been described. Here, we describe an approach that allows robust and reproducible measurement of gating-associated charge movements in Hv1. Gating currents reveal that VS activation and proton-selective aqueous conductance opening are thermodynamically distinct steps in the Hv1 activation pathway and show that pH changes directly alter VS activation. The availability of an assay for gating currents in Hv1 may aid future efforts to elucidate the molecular mechanisms of gating cooperativity, pH-dependent modulation, and H+ selectivity in a model VS domain protein. |
| Databáze: | OpenAIRE |
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