rPsalmotoxin 1 (rPcTx1)
- 貨號 Cat. No.
- RTP-100
- 規格 Size
- 5 μg 5x5 μg 10μg 5x10μg 0.1mg
Description
rPsalmotoxin 1 (rPcTx1)
A Novel and Potent Specific Blocker of ASIC 1a Channel
| Product#: | RTP-100 |
| Sizes: |
| 5 mg |
| 5 x 5 mg |
| M.W.: | 4695.4 |
| Sequence: | EDCIPKWKGCVNRHGDCCEGLECWKRRRSFEVCVPKTPKT |
| Purity: | >99% |
| Bioassay: |
rPsalmotoxin (#RTP-100) inhibits the cation current of ASIC 1a expressed in Xenopus oocyte. |
 |
Xenopus Oocyte membrane potential was held at 5mV and whole cell current was continuously recorded using TEVC. ASIC1a currents were elicited by rapid (~2sec) exposure to pH 5 in physiological solution (indicated by arrows). During the time indicated by the horizontal bar, 5nM rPcTx1 were introduced into the bath via perfusion, resulting in a complete, yet fairly reversible inhibition of the pH dependent inward transients. |
Native Psalmotoxin1 (PcTx1) is 40-amino acid peptidyl toxin originally isolated from the venom of South American tarantula Psalmopoeus cambridgei.1
PcTx1 potently (IC50 = 0.9 nM) and specifically blocks a particular subclass of H+-gated cation channels the Acid-sensing ion channels 1a (ASIC1a) and does blocks the activity of its splice variant ASIC1b (which differs only in their N-terminal sequence) or other ASIC isoform. Moreover PcTX1 looses its capacity to block ASIC1a as soon as this subunit is associated with another member of the family (ASIC2a or ASIC3). The ASICs are abundant in the brain and spinal cord neurons and are implicated in pain sensation, ischemic stroke mechanosensation, learning and memory.2,3 In acute and neuropathic pain models specific blockage of ASIC1a with PcTx1 results in analgesic effects working upstream of the opiate receptors.4
PcTx1 is characterized by the unusual quadruplet Lys25-Arg26-Arg27-Arg28, which probably forms a strongly positive "patch" at the surface of the toxin molecule, constituting an area that is a strong candidate for channel binding site recognition. The molecular scaffold of PcTx1 is likely to be similar to that previously described for both cone snail and spider toxins5,6 and comprises a triple-stranded antiparallel b-sheet structure reticulated by three disulfide bridges.1
Using iodinated form of the toxin, the binding for PcTx1 site identifies at the cysteine-rich domains I and II (CRDI and CRDII) of the extracellular loop of ASIC1a. Disulphide bridge between domains 1 and 4 of the channel supports a close relationship between the CRDI4RDII domain, where PcTx1 acts, and the post-M1 region the binding site for the proton7.
Alomone Labs is pleased to offer rPsalamotoxin, a recombinant peptide expressed in and extracted from E. coli and purified to homogeneity.