PROSITE documentation PDOC60022
Huwentoxin-2 family signature


The spider venoms often contain many active peptides such as neurotoxins, lectins, inhibitors to enzyme, etc. These peptides are very important for spider's hunting and defending. During the long history of spider evolution, the peptides evolved into different structures and functions. The following peptides share high similarity and belong to the huwentoxin-2 family [1,2,3,4]:

  • Ornithoctonus huwena (Chinese bird spider) (Selenocosmia huwena) huwentoxin-II (HWTX-II) and huwentoxin-IIa (HWTX-IIa), which can cause reversatile paralysis in insects and are insecticidal toxins.
  • Ornithoctonus huwena (Chinese bird spider) (Selenocosmia huwena) huwentoxin-VII (HWTX-VII) and huwentoxin-VIII (HWTX-VIII), which block neuromuscular transmission.
  • Ornithoctonus huwena (Chinese bird spider) (Selenocosmia huwena) huwentoxin-VI (HWTX-VI).
  • Brachypelma smithii (Mexican red knee tarantula) venom protein 1.
  • Lasiodora parahybana (Salmon pink birdeater) lasiotoxin 1 and 2, which are toxic to mice, but not insects.
  • Eurypelma californica (American tarantula) ESTX1 and ESTX2 neurotoxins.

Peptides of the huwentoxin-2 family contain 6 cysteine residues involved in three disulfide bonds. The three disulfid bridges of HWTX-II have been assigned as C1-C3, C2-C5 and C4-C6 [3]. The structure of HWTX-II contains two β-turns and a double stranded antiparallel β-sheet cross-linked by two disulfide bonds (2-5 and 4-6) (see <PDB:1I25>). Due to its unique 1-3,2-5,4-6 disulfide bond-pairing, HTWX-II does not form a cystine-knot like other spider toxins [4].

We developed a pattern for huwentoxin-2 family proteins, which contains the six conserved cysteines.

Expert(s) to contact by email:

Ramakumar S.

Last update:

August 2005 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

HWTX_2, PS60022; Huwentoxin-2 family signature  (PATTERN)


1TitleLiang S.-P. An overview of peptide toxins from the venom of the Chinese bird spider Selenocosmia huwena Wang [=Ornithoctonus huwena (Wang)].
SourceToxicon 43:575-585(2004).
PubMed ID15066414

2AuthorsDiao J. Lin Y. Tang J. Liang S.
TitlecDNA sequence analysis of seven peptide toxins from the spider Selenocosmia huwena.
SourceToxicon 42:715-723(2003).
PubMed ID14757201

3AuthorsShu Q. Huang R. Liang S.-P.
TitleAssignment of the disulfide bonds of huwentoxin-II by Edman degradation sequencing and stepwise thiol modification.
SourceEur. J. Biochem. 268:2301-2307(2001).
PubMed ID11298747

4AuthorsShu Q. Lu S.-Y. Gu X.-C. Liang S.-P.
TitleThe structure of spider toxin huwentoxin-II with unique disulfide linkage: evidence for structural evolution.
SourceProtein Sci. 11:245-252(2002).
PubMed ID11790834

PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)