1Y29
Three dimensional solution structure of huwentoxin-x by 2D 1H-NMR
Summary for 1Y29
| Entry DOI | 10.2210/pdb1y29/pdb |
| Descriptor | huwentoxin-x (1 entity in total) |
| Functional Keywords | a double-stranded beta-sheet, ick, knottin, toxin |
| Cellular location | Secreted: P68424 |
| Total number of polymer chains | 1 |
| Total formula weight | 2942.57 |
| Authors | |
| Primary citation | Liu, Z.,Dai, J.,Dai, L.,Deng, M.,Hu, Z.,Hu, W.,Liang, S. Function and solution structure of Huwentoxin-X, a specific blocker of N-type calcium channels, from the Chinese bird spider Ornithoctonus huwena J.Biol.Chem., 281:8628-8635, 2006 Cited by PubMed Abstract: Huwentoxin-X (HWTX-X) is a novel peptide toxin, purified from the venom of the spider Ornithoctonus huwena. It comprises 28 amino acid residues including six cysteine residues as disulfide bridges linked in the pattern of I-IV, II-V, and III-VI. Its cDNA, determined by rapid amplification of 3' and 5' cDNA ends, encodes a 65-residue prepropeptide. HWTX-X shares low sequence homology with omega-conotoxins GVIA and MVIIA, two well known blockers of N-type Ca2+ channels. Nevertheless, whole cell studies indicate that it can block N-type Ca2+ channels in rat dorsal root ganglion cells (IC50 40 nm) and the blockage by HWTX-X is completely reversible. The rank order of specificity for N-type Ca2+ channels is GVIA approximately HWTX-X > MVIIA. In contrast to GVIA and MVIIA, HWTX-X had no detectable effect on the twitch response of rat vas deferens to low frequency electrical stimulation, indicating that HWTX-X has different selectivity for isoforms of N-type Ca2+ channels, compared with GVIA or MVIIA. A comparison of the structures of HWTX-X and GVIA reveals that they not only adopt a common structural motif (inhibitor cystine knot), but also have a similar functional motif, a binding surface formed by the critical residue Tyr, and several basic residues. However, the dissimilarities of their binding surfaces provide some insights into their different selectivities for isoforms of N-type Ca2+ channels. PubMed: 16439354DOI: 10.1074/jbc.M513542200 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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