ISSN:
1573-4943
Keywords:
Phospholipase A2
;
myotoxin
;
bothropstoxin
;
B. jararacussu
;
sequence homology
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The complete amino acid sequence of bothropstoxin-I (BthTX-I), a myotoxin isolated fromBothrops jararacussu snake venom, is reported. The results show that BthTX-I is a Lys49 phospholipase A2 (PLA2)-like protein composed of a single polypeptide chain of 121 amino acid residues (M r=13,720), containing one methionine and 14 half-cystines. Although deprived of any detectable PLA2 activity, BthTX-I reveals a high degree of sequence homology with Asp49-PLA2s and with other Lys49-myotoxins. Critical mutations—such as Leu5 for Phe5; Gln11 for X11; Asn28 for Tyr28; Leu32 for Gly32; Lys49 for Asp49; and Asp71 for Asn71—which are apparently involved with the decreasing or elimination of PLA2 activity, have been detected. The same mutations occurred in myotoxin II fromBothrops asper venom, but five extra changes—namely, Pro90 for Ser90; Gly111 for Asn111; His120 for Tyr120; Phe124 for Leu124; and Pro132 for Ala132—have been found relative to myotoxin II.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01024915
