{PDOC60029}
{PS60029; SPIDER_CSTX}
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* Spider toxin CSTX family signature *
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Spider toxins  of  the  CSTX  family  are  ion  channel  toxins  containing an
inhibitor cystine  knot  (ICK)  structural  motif  or  Knottin  scaffold  (see
<PDOC60004>) [E1].  The  four disulfide bonds present in the CSTX spider toxin
family are arranged in the following pattern: 1-4, 2-5, 3-8 and 6-7.

This family includes:

 - Cupiennius  salei  (Wandering  spider)  toxin  CSTX-1  and  its proteolytic
   products CSTX-2a and CSTX-2b [1].
 - Cupiennius salei (Wandering spider) CSTX-9 [2].
 - Cupiennius  salei  (Wandering  spider)  CSTX-13,  a neurotoxic enhancer. In
   contrast to  CSTX-1  and  CSTX-9,  CSTX-13  is a two-chain peptide with two
   interchain and two intrachain disulfide bridges [3].

We have  developed  a pattern that contains the six conserved cysteines with a
cysteine arrangement  C-C-CC-C-C  which  are  also  found  in  the  A chain of
CSTX-13.

-Conserved pattern: C-{C}(6)-C-{C}(6)-C-C-{C}(8)-C-{C}-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: February 2006 / First entry.

[ 1] Kuhn-Nentwig L., Schaller J., Kaempfer U., Imboden H., Malli H.,
     Nentwig W.
     "A lysine rich C-terminal tail is directly involved in the toxicity of
     CSTX-1, a neurotoxic peptide from the venom of the spider Cupiennius
     salei."
     Arch. Insect Biochem. Physiol. 44:101-111(2000).
     PubMed=10897091; DOI=10.1002/1520-6327(200007)44:3<101::AID-ARCH1>3.0.CO;2-S
[ 2] Schaller J., Kaempfer U., Schuerch S., Kuhn-Nentwig L., Haeberli S.,
     Nentwig W.
     "CSTX-9, a toxic peptide from the spider Cupiennius salei: amino acid
     sequence, disulphide bridge pattern and comparison with other spider
     toxins containing the cystine knot structure."
     Cell. Mol. Life Sci. 58:1538-1545(2001).
     PubMed=11693532
[ 3] Wullschleger B., Kuhn-Nentwig L., Tromp J., Kaempfer U., Schaller J.,
     Schuerch S., Nentwig W.
     "CSTX-13, a highly synergistically acting two-chain neurotoxic
     enhancer in the venom of the spider Cupiennius salei (Ctenidae)."
     Proc. Natl. Acad. Sci. U.S.A. 101:11251-11256(2004).
     PubMed=15272079; DOI=10.1073/pnas.0402226101
[E1] https://bioserv.cbs.cnrs.fr

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