{PDOC60022} {PS60022; HWTX_2} {BEGIN} ********************************* * 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 [1-4]: - 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 beta-turns and a double stranded antiparallel beta-sheet cross-linked by two disulfide bonds (2-5 and 4-6) (see ). 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. -Conserved pattern: C-x(1,4)-[FLIV]-[SEP]-C-[DE]-[EIQ]-x(4,7)-C-x(0,7)-C- [KST]-x(4,18)-C-[YK]-x(1,3)-C [The 6 C's are involved in disulfide bonds] -Sequences known to belong to this class detected by the pattern: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Expert(s) to contact by email: Ramakumar S.; ramak@physics.iisc.ernet.in -Last update: August 2005 / First entry. [ 1] Liang S.-P. "An overview of peptide toxins from the venom of the Chinese bird spider Selenocosmia huwena Wang [=Ornithoctonus huwena (Wang)]." Toxicon 43:575-585(2004). PubMed=15066414; DOI=10.1016/j.toxicon.2004.02.005 [ 2] Diao J., Lin Y., Tang J., Liang S. "cDNA sequence analysis of seven peptide toxins from the spider Selenocosmia huwena." Toxicon 42:715-723(2003). PubMed=14757201 [ 3] Shu Q., Huang R., Liang S.-P. "Assignment of the disulfide bonds of huwentoxin-II by Edman degradation sequencing and stepwise thiol modification." Eur. J. Biochem. 268:2301-2307(2001). PubMed=11298747 [ 4] Shu Q., Lu S.-Y., Gu X.-C., Liang S.-P. "The structure of spider toxin huwentoxin-II with unique disulfide linkage: evidence for structural evolution." Protein Sci. 11:245-252(2002). PubMed=11790834 -------------------------------------------------------------------------------- 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 https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}