1qk6

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Solution structure of huwentoxin-I by NMRSolution structure of huwentoxin-I by NMR

Structural highlights

1qk6 is a 1 chain structure with sequence from Cyriopagopus schmidti. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:Solution NMR, 10 models
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

TXH1_CYRSC Lethal toxin with multiple biological activities. Inhibits voltage-gated TTX-sensitive sodium channels in DRG neurons (IC(50)=55 nM) and also shows activity when directly tested on Nav1.7/SCN9A (IC(50)=25.1-630 nM) (PubMed:17451655, PubMed:21731778, PubMed:31234412). Inhibits N-type calcium channels (Cav2.2/CACNA1B (IC(50)=100 nM)) (PubMed:11024489, PubMed:17451655). Also blocks neuromuscular transmission (PubMed:10736477, PubMed:8212049, PubMed:9028007). In vivo, intrathecal injected toxin shows analgesic activity in the rat formalin-induced pain model, without induction of motor dysfunction in rats.[1]

Publication Abstract from PubMed

The three-dimensional structure in aqueous solution of native huwentoxin-I, a neurotoxin from the venom of the spider Selenocosmia huwena, has been determined from two-dimensional H NMR data recorded at 500 and 600 MHz. Structural constraints consisting of interproton distances inferred from NOEs and dihedral angles from spin-spin coupling constants were used as input for distance geometry calculation with the program XPLOR 3.1. The best 10 structures have NOE violations < 0.3 A, dihedral violations < 2 degrees, and pairwise root-mean-square differences of 1.08 (+/- 0.20) A over backbone atoms (N, C alpha, C). The molecule adopts a compact structure consisting of a small triple-stranded antiparallel beta-sheet and five beta-turns. A small hydrophobic patch consisting of Phe 6, Trp 28, and Trp 31 is located on one side of the molecule. All six lysine residues are distributed on the molecular surface. The three disulfide bridges are buried within the molecule. The structure contains an "inhibitor cystine knot motif" which is adopted by several other small proteins, such as omega-conotoxin, agatoxin IVA, and gurmarin.

Proton nuclear magnetic resonance studies on huwentoxin-I from the venom of the spider Selenocosmia huwena: 2. Three-dimensional structure in solution.,Qu Y, Liang S, Ding J, Liu X, Zhang R, Gu X J Protein Chem. 1997 Aug;16(6):565-74. PMID:9263120[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Chen JQ, Zhang YQ, Dai J, Luo ZM, Liang SP. Antinociceptive effects of intrathecally administered huwentoxin-I, a selective N-type calcium channel blocker, in the formalin test in conscious rats. Toxicon. 2005 Jan;45(1):15-20. PMID:15581678 doi:10.1016/j.toxicon.2004.08.018
  2. Qu Y, Liang S, Ding J, Liu X, Zhang R, Gu X. Proton nuclear magnetic resonance studies on huwentoxin-I from the venom of the spider Selenocosmia huwena: 2. Three-dimensional structure in solution. J Protein Chem. 1997 Aug;16(6):565-74. PMID:9263120
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