A purified protein fraction of Bacillus thuringiensis subsp. aizawai (HD-133)-activated toxin was subjected to amino acid modification by phenylglyoxal as an arginine-directed reagent. The effect of phenylglyoxylation was assayed on the K (+)-dependent accumulation of leucine into brush border membrane vesicles from Bombyx mori larval midgut. Phenylglyoxal inactivates the toxin in a dose-and time-dependent manner. Loss of inhibitory effect of the toxin followed a pseudo-first-order kinetics. Observed rates of inactivation were linearly dependent upon the square of phenylglyoxal concentration and a second-order constant of 4.17 M(-2) min(-1) was calculated. These results indicate the involvement of highly reactive arginine residues in the formation of specific toxin domains implicated in the interaction with membrane receptor(s)
Villa, M., Giglione, C., Hanozet, G., Parenti, P. (1994). Chemical modification of bacillus-thuringiensis subsp aizawai delta-endotoxin - implication of arginine residues in bombyx-mori toxicity. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY, 50(1), 15-22 [10.1006/pest.1994.1053].
Chemical modification of bacillus-thuringiensis subsp aizawai delta-endotoxin - implication of arginine residues in bombyx-mori toxicity
Parenti, P.
1994
Abstract
A purified protein fraction of Bacillus thuringiensis subsp. aizawai (HD-133)-activated toxin was subjected to amino acid modification by phenylglyoxal as an arginine-directed reagent. The effect of phenylglyoxylation was assayed on the K (+)-dependent accumulation of leucine into brush border membrane vesicles from Bombyx mori larval midgut. Phenylglyoxal inactivates the toxin in a dose-and time-dependent manner. Loss of inhibitory effect of the toxin followed a pseudo-first-order kinetics. Observed rates of inactivation were linearly dependent upon the square of phenylglyoxal concentration and a second-order constant of 4.17 M(-2) min(-1) was calculated. These results indicate the involvement of highly reactive arginine residues in the formation of specific toxin domains implicated in the interaction with membrane receptor(s)
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