• KcsA

    Representative current trace recorded from a planar lipid bilayer in which purified KcsA channels were reconstituted (measured on the Port-a-Patch)

KcsA - Prokaryotic pH-gated Potassium Channel

Prokaryotic Tetrameric Potassium Channels

The channel protein contains two transmembrane helices (M1 and M2). The channel itself is a tetramer composed of four identical subunits so that the M2 helix faces the central pore, while the other M1 helix faces the lipid membrane.

History and function:
KcsA was the first potassium ion channel to be characterized using x-ray crystallography by Roderick MacKinnon and his colleagues in 1998. As one of the most studied ion channels to this day, KcsA is a template for research on K+ channel function. The KcsA channel is considered a model channel because its structure provides a framework for understanding K+ channel conduction, which has three parts: Potassium selectivity, channel gating by pH sensitivity, and voltage-gated channel inactivation.

Data and Applications

KcsA - Single Channel Recordings

Icon Orbit   Orbit16 Ionera KcsAOrbit 16 and applications:
Data were kindly provided by Ionera.

Single channel currents of tetrameric potassium channel KcsA E71A recorded from 5 selected bilayers in parallel.
KcsA was expressed in vitro with its co-translational integration into liposoms containing asolectin lipids. The proteoliposomes were subsecuently fused with bilayer array containing POPE/POPG on the Orbit 16.
Conditions: Current traces were recorded in 20 mM MES pH 4.0 on the cis-side and 10 mM MOPS, pH 7.0 on the trans-side of the bilayer; containing 200 mM KCl symmetric solutions with membrane potential held at +150 mV.

KcsA - Bilayer Recordings

KCSA Vesicle prep proicon vpp   Vesicle Prep Pro data and applicatons:

The image shows a representative current trace recorded from a planar lipid bilayer in which purified KcsA channels were reconstituted (100 mM KCl, asymmetric pH; pH 4/pH 7). A ramp from -100 mV to +100 mV was used to evoke the single channel events.

Download: Application Note

Application Notes

KcsA - "Lipid bilayer recordings of KcsA channels reconstituted in proteoliposomes"

icon pap   Port-a-Patch and   icon vpp   Vesicle Prep Pro application note:  logo pdf   (0.2 MB)



2018 - Functional Analysis of Membrane Proteins Produced by Cell-Free Translation

icon pap   Port-a-Patch and    Icon Orbit Mini   Orbit mini article in Protein Engineering (2018)

2016 - Structural and functional characterization of a calcium-activated cation channel from Tsukamurella paurometabola

icon pap  Port-a-Patch and   icon vpp   Vesicle Prep Pro publication in Nature Communications (2016)

2014 - Membrane assembly of the functional KcsA potassium channel in a vesicle-based eukaryotic cell-free translation system

icon pap  Port-a-Patch and   icon vpp   Vesicle Prep Pro publication in Biosensors and Bioelectronics (2014)

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