Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10880272 | Toxicon | 2005 | 12 Pages |
Abstract
Kv4 voltage-gated K+ channels are responsible for transient K+ currents in the central nervous system and in the heart. HpTx2 is a peptide toxin that selectively inhibits these currents; making it a useful probe for understanding Kv4 channel structure and drug binding. Therefore, we developed a method to produce large amounts of recombinant HpTx2. Recombinant toxin inhibits all three Kv4 isoforms to the same degree; however, the voltage-dependence of inhibition is less apparent for Kv4.1 than for Kv4.3. Similarly, recombinant HpTx2GS effects gating characteristics of both channels, but Kv4.1 to a much lesser degree. The toxin lacks affinity for Kv1.4, Kv2.1, and Kv3.4. To locate the binding site, the amino acids linking the third and forth membrane spanning segments of Kv4.3 were replaced with analogous amino acids of Kv1.4. The chimeric K+ channel was completely insensitive to block by rHpTx2, suggesting that its binding site is near the channel's voltage sensor. These data show that rHpTx2GS is a gating modifier toxin that binds to a site remote from the pore.
Keywords
4-(2-hydroxyethyl)-1-piperazine ethane sulfonic acidICKHEPESOD600IMACnuclear magnetic resonanceEDTAethylene diamine tetra acetateITOoptical density at 600 nmNMRIon channel gatingMatrix-assisted laser desorption ionization time-of-flight mass spectrometryMALDI-TOF MSPotassium channel blockersVoltage-gatedRecombinant fusion proteinsPotassium channelsHigh pressure liquid chromatographyHPLCimmobilized metal affinity chromatographyInhibitor cystine knot
Related Topics
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Biochemistry, Genetics and Molecular Biology
Biochemistry, Genetics and Molecular Biology (General)
Authors
Vladislav V. Zarayskiy, Ganesh Balasubramanian, Vladimir E. Bondarenko, Michael J. Morales,