Protein family
Myotoxins are small, basic peptides found in snake venoms (e.g. rattlesnakes )[ 2] [ 3] and lizard venoms (e.g. Mexican beaded lizard ).[ 4] This involves a non-enzymatic mechanism that leads to severe muscle necrosis . These peptides act very quickly, causing instantaneous paralysis to prevent prey from escaping and eventually death due to diaphragmatic paralysis.
The first myotoxin to be identified and isolated was crotamine , from the venom of Crotalus durissus terrificus , a tropical South American rattlesnake, by Brazilian scientist José Moura Gonçalves , in the 1950s. Its biological actions, molecular structure and gene responsible for its synthesis were all elucidated in the last two decades.
^ Nicastro G, Franzoni L, de Chiara C, Mancin AC, Giglio JR, Spisni A (May 2003). "Solution structure of crotamine, a Na+ channel affecting toxin from Crotalus durissus terrificus venom" . Eur. J. Biochem . 270 (9): 1969– 79. doi :10.1046/j.1432-1033.2003.03563.x . PMID 12709056 .
^ Griffin PR, Aird SD (1990). "A new small myotoxin from the venom of the prairie rattlesnake (Crotalus viridis viridis)" . FEBS Lett . 274 (1): 43– 47. Bibcode :1990FEBSL.274...43G . doi :10.1016/0014-5793(90)81325-I . PMID 2253781 . S2CID 45019479 .
^ Samejima Y, Aoki Y, Mebs D (1991). "Amino acid sequence of a myotoxin from venom of the eastern diamondback rattlesnake (Crotalus adamanteus)". Toxicon . 29 (4): 461– 468. Bibcode :1991Txcn...29..461S . doi :10.1016/0041-0101(91)90020-r . PMID 1862521 .
^ Whittington, CM; Papenfuss, AT; Bansal, P; Torres, AM; Wong, ES; Deakin, JE; Graves, T; Alsop, A; Schatzkamer, K; Kremitzki, C; Ponting, CP; Temple-Smith, P; Warren, WC; Kuchel, PW; Belov, K (Jun 2008). "Defensins and the convergent evolution of platypus and reptile venom genes" . Genome Research . 18 (6): 986– 94. doi :10.1101/gr.7149808 . PMC 2413166 . PMID 18463304 .