Characterization of myotoxin a from the venom of prairie rattlesnake (Crotalus viridis viridis)

Abstract

A previously unknown polypeptide myotoxin, designated myotoxin a, was isolated for the first time from prairie rattlesnake (Crotalus viridis viridis) venom. Electrophoretic homogeneity of myotoxin a was shown in beta-alanine disc gel polyacrylamide gel electrophoresis and in isoelectric focusing gel electrophoresis. Molecular weight and isoelectric point estimates of 4100 and 9.6 were obtained by gel filtration and isoelectric focusing gel electrophoresis, respectively. Amino acid composition showed a total of 39 amino acid residues, with 10 lysine residues and two disulfide bridges. When the two disulfide brides were reduced and alkylated, the myotoxic activity was abolished, indicating that the disulfide bridges of myotoxin a are essential for its biological activity. The loss of the biological activity is probably due to a marked change in secondary structure. The circular dichroic spectrum indicates that the chemically modified, inactive myotoxin exhibits typical random-coil conformation.

Correcting the Circular Dichroism Spectra of Peptides for Contributions of Absorbing Side Chains

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far UV have demonstrated unusual CD spectra due The aromatic and sulfur-containing side chains Trp, to aromatic side chains (13)(14)(15)(16)(17)(18)(19)(20)(21)(22). In most cases, the Tyr, Phe, Cys, and Met contribute to the CD spectra of tryptophan and tyrosine sidechains are found to be the peptides and proteins in the amide region, interfering sources of interference.

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CIDNP study of the aromatic side chain interactions in myotoxina

“…Myotoxin a was isolated from the crude venom of Crotalus viridis viridis by gel filtration followed by cation exchange chromatography, as described by Cameron and Tu (1977). Myotoxin a fragment 1-11 was prepared by solid-phase peptide synthesis (Utaisincharoen et al, 1991;Tu et al, 1992).…”

Neutralization of edema, hemorrhage and myonecrosis induced by North American crotalid venoms in simulated first-aid treatments

“…The best known, and most widely studied is myotoxin a, from C. viridis viridis (Ownby et aI., 1976;Cameron and Tu, 1977). Myotoxin a is composed of 42 amino acid residues and has a molecular weight of about 4000 (Fox et aI., 1979).…”