Molecular Interactions Involved in KCSA pH Gating
نویسندگان
چکیده
منابع مشابه
Molecular interactions involved in proton-dependent gating in KcsA potassium channels
The bacterial potassium channel KcsA is gated open by the binding of protons to amino acids on the intracellular side of the channel. We have identified, via channel mutagenesis and x-ray crystallography, two pH-sensing amino acids and a set of nearby residues involved in molecular interactions that influence gating. We found that the minimal mutation of one histidine (H25) and one glutamate (E...
متن کاملMolecular mechanism of pH sensing in KcsA potassium channels.
The bacterial potassium channel KcsA is gated by high concentrations of intracellular protons, allowing the channel to open at pH < 5.5. Despite prior attempts to determine the mechanism responsible for pH gating, the proton sensor has remained elusive. We have constructed a KcsA channel mutant that remains open up to pH 9.0 by replacing key ionizable residues from the N and C termini of KcsA w...
متن کاملMolecular Architecture of Full-Length KcsA Role of Cytoplasmic Domains in Ion Permeation and Activation Gating
The molecular architecture of the NH 2 and COOH termini of the prokaryotic potassium channel KcsA has been determined using site-directed spin-labeling methods and paramagnetic resonance EPR spectroscopy. Cysteine mutants were generated (residues 5–24 and 121–160) and spin labeled, and the X-band CW EPR spectra were obtained from liposome-reconstituted channels at room temperature. Data on prob...
متن کاملGlobal Twisting Motion of Single Molecular KcsA Potassium Channel upon Gating
Ion channels are signal transduction molecules that switch ion permeation pathways on and off (gating). Crystal structures of several kinds of potassium channels have revealed open and closed conformations, which provide static pictures of gating status. Here we studied KcsA potassium channels undergoing conformational changes at the single-molecule level. A KcsA channel with a gold nanocrystal...
متن کاملA Quantitative Description of KcsA Gating I: Macroscopic Currents
The prokaryotic K(+) channel KcsA is activated by intracellular protons and its gating is modulated by transmembrane voltage. Typically, KcsA functions have been studied under steady-state conditions, using macroscopic Rb(+)-flux experiments and single-channel current measurements. These studies have provided limited insights into the gating kinetics of KcsA due to its low open probability, unc...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2011
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2010.12.1700