Amino acid sequence of a myotoxin from venom of the eastern diamondback rattlesnake (Crotalus adamanteus)

Y. Samejima, Y. Aoki and D. Mebs. Amino acid sequence of a myotoxin from venom of the eastern diamondback rattlesnake ( Crotalus adamanteus). Toxicon 29, 461–468, 1991.—The complete amino acid sequence of a myotoxin isolated from Crotalus adamanteus venom (CAM-toxin) was determined. The total number of amino acid residues was 45, giving a mol. wt of 5202. The amino acid sequence was compared with those of previously determined Crotalus myotoxins. The CAM-toxin shows a surprisingly close relationship to those of peptide c ( C. v. helleri), myotoxin a ( C. v. viridis), crotamine ( C. d. terrificus), myotoxin I and II ( C. v. concolor) with homologies of approximately 98, 83, 90, 95 and 91%, respectively. The hydropathy profile of the CAM-toxin is almost identical to peptide c and myotoxin I, as can be assumed from the sequence homology. Despite the absence of any close sequence homology with the myotoxic phospholipase A ₂ enzymes, CAM-toxin contains a similar cationic myotoxic region at residues 2–10 as found in the other five myotoxic peptides.