rMaurotoxin
- 貨號 Cat. No.
- RTM-340
- 規格 Size
- 5 μg 5x μg 10μg 5xμg 0.1mg
Description
rMaurotoxin
Novel Blocker of KCa2 (SK) K+ Channels
| Product#: | RTM-340 |
| Sizes: |
| 5 mg |
| 5 x mg |
| 10 mg |
| 5 x mg |
| 0.1 mg |
| M.W.: | 3613 |
| Sequence: | VSCTGSKDCY APCRKQTGCP NAKCINKSCK CYGC |
 | NMR structure of Maurotoxin (1TXM).8 MTX belongs to the a-KTX-6 scorpion toxin family. 2 |
| Purity: | >98% |
| Bioassay: |
Inhibition of K+ channels by rMaurotoxin and rScyllatoxin. |
 |
| Legend A (see above) Inhibition of KCa2.2 channels expressed in Xenopus oocytes by rScyllatoxin and by rMaurotoxin. Continuous current recording at holding potential +5 mV with low Cl- content in the bath solution. An outward current (upward deflection) carried out by K+ ions flowing via KCa2.2 channels develops following an intra-oocyte Ca2+ injection (arrow). Both recombinant toxins partially and reversibly depressed the K+ current at 200 nM. Periods of toxin perfusion are marked by the horizontal bars. |
 |
Legend B (see above) Inhibition of KV1.2 channels expressed in Xenopus oocytes by rMaurotoxin. Right: Time course of KV1.2 current amplitude and its changes upon application and wash of 20 nM rMaurotoxin. Period of toxin perfusion is marked by the horizontal bar. Left: Example current traces before (red) and during application of 20 nM rMaurotoxin. |
| References: |
1. | Kharrat, R. et al. (1996) Eur. J. Biochem. 242, 491. |
2. | Rodriguez de la Vega, R.C. and Possani, L.D. (2004) Toxicon 43, 865. |
3. | Kharrat, R. et al. (1997) FEBS. Lett. 406, 284. |
4. | Carlier, E. et al. (2000) J. Pept. Res. 55, 419. |
5. | Castle, N.A. et al. (2003) Mol. Pharmacol. 63, 409. |
6. | Visan, V. et al. (2004) Toxicon. 43, 973. |
7. | Visan, V. et al. (2004) Mol. Pharmacol. 66, 1103. |
8. | Blanc, E. et al. (1997) Proteins 29, 321. |
Maurotoxin (MTX) is a 34 amino acid long toxin, originally isolated from the venom of the scorpion Scorpio Maurus palmatus, and is classified as a-KTx6.2 scorpion toxin family, having four disulfide bridges (P80719).1,2
MTX activity was extensively assayed on a large array of K+ channels, including KCa (KCa1.1, KCa2.1, KCa2.2, KCa2.2, KCa3.1), KCNA (KCNA1, KCNA2and KCNA3) and Shaker B K+ currents. MTX was able to inhibit the binding of 125I -apamin and 125I Kaliotoxin to rat brain synaptosomal membranes with IC50 of 5nM and 30pM, respectively.3 Furthermore, MTX was able to block KCNA1(KV1.1), KCNA2(KV1.2) and KCNA3(KV1.3) expressed in Xenopus oocyes with IC50 of 45nM, 0.8nM, and 180nM, respectively.3 MTX was also able to block Shaker-B K+ current with an IC50 of 2 nM.4 In contrast to previous reports, MTX was recently shown to produce no inhibition of KCa1.1, KCa2.1, KCa2.2, KCa2.2 small conductance KCa channels up to 300 nM in physiologically relevant ionic strength buffers, but rather produced a high and specific block towards KCa3.1(IKca1, SK4) and KCNA2 (KV1.2) with IC50 of 1nM and 0.1nM, respectively.5 Furthermore, MTX was shown to block Gardos channel in human red blood cells and to inhibit the KCa in activated human T-lymphocytes without affecting the voltage-gated K+ current encoded by KCNA3.5 Moreover, MTX inhibition was shown to be pH-dependent.6,7
In conclusion, Maurotoxin seems to be a very potent blocker of either KCa3.1 and KCNA2 channels.