{PDOC00435}
{PS00459; MYOTOXINS_1}
{PS51345; MYOTOXINS_2}
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* Myotoxins family signature and profile *
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Myotoxins [1,2] are small basic peptides (42 to 45 residues) from the venom of
rattlesnakes  that  cause severe muscle necrosis by a non-enzymatic mechanism.
Myotoxins  act  extremely  rapidly and serve two primary biological functions:
limiting  the  flight  of  prey by causing instantaneous paralysis of the hind
limbs and promoting rapid death by paralysis of the diaphragm.

Myotoxins contain six cysteines involved in three disulfide bonds  as shown in
the following schematic representation:

                    +------------------+
                    |                  |
          x+xC+x+xx+Cxx+xxxCxxxxxxxx+xxCxx+x+CC++xxxxxx
             |             |                 ||
             +-------------|-----------------+|
                           +------------------+

'C': conserved cysteine involved in a disulfide bond.
'+': conserved basic residue (Arg, Lys, or His).

The structure  of all known myotoxins is very conserved. We chose  to  build a
pattern based  solely  on  the  position  of  conserved  cysteines  and  basic
residues. We also developed a profile that covers the whole myotoxin.

-Consensus pattern: K-x-C-H-x-K-x(2)-H-C-x(2)-K-x(3)-C-x(8)-K-x(2)-C-x(2)-
                    [RK]-x-K-C-C-K-K
                    [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.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: December 2007 / Text revised; profile added.

[ 1] Griffin P.R., Aird S.D.
     "A new small myotoxin from the venom of the prairie rattlesnake
     (Crotalus viridis viridis)."
     FEBS Lett. 274:43-47(1990).
     PubMed=2253781
[ 2] Nicastro G., Franzoni L., de Chiara C., Mancin A.C., Giglio J.R.,
     Spisni A.
     "Solution structure of crotamine, a Na+ channel affecting toxin from
     Crotalus durissus terrificus venom."
     Eur. J. Biochem. 270:1969-1979(2003).
     PubMed=12709056

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