{PDOC60015}
{PS60015; MU_AGATOXIN}
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********************************
* Mu-agatoxin family signature *
********************************

Spider mu-agatoxins  are  cysteine-rich insecticidal polypeptides, which cause
gradual but  irreversible  paralysis. These toxins cause repetitive firing and
massive transmitter  release  (which  is mediated by glutamate receptors) from
presynaptic stores at neuromuscular junctions [1].

The mu-agatoxin family contains:

 - Mu-agatoxin 1-6 from Agelenopsis aperta (Funnel-web spider),
 - Curtatoxin 1-3 from Hololena curta (Funnel-web spider),
 - Delta-palutoxin IT1, IT2, IT3 and IT4 from Paracoelotes luctuosus (Spider),
 - Toxin  ACTX-Hi:OB4219  from  Hadronyche  infensa  (Fraser island funnel-web
   spider).

Mu-agatoxin family  proteins have a [C-C-CC-C-C-C-C] cysteine arrangement. The
three dimensional  structure  of mu-agatoxins possesses a knottin scafold (see
<PDOC60004>) [E1]  with  a fourth pair of cysteine residues (marked '#' in the
following schematic representation) involved in a vicinal disulfide linkage.

                              +-------------+
                              |             | #     #
                       CxxxxxxCxxxxxxxCCxxxxCxCxxxxxCxC
                       |              ||      |     | |
                       +---------------+      +-----+ |
                                      +---------------+

'C': conserved cysteine involved in a disulfide bond.
'#': fourth pair of cysteine residues.

Our signature  pattern for mu-agatoxins contains the eight conserved cysteines
involved in disulfide bonds.

-Consensus pattern: C-[LAV]-x-[DEK]-X(3)-C-x(6,7)-C-C-x(4)-C-x-C-x(5)-C-x-C
                    [The 8 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: June 2005 / First entry.

[ 1] Skinner W.S., Adams M.E., Quistad G.B., Kataoka H., Cesarin B.J.,
     Enderlin F.E., Schooley D.A.
     "Purification and characterization of two classes of neurotoxins from
     the funnel web spider, Agelenopsis aperta."
     J. Biol. Chem. 264:2150-2155(1989).
     PubMed=2914898
[E1] https://bioserv.cbs.cnrs.fr

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