Polyacrylamide gel electrophoretic studies on the self-association of crotamine: characterization and molecular dimension of n-mer species.
Polyacrylamide gel electrophoresis (PAGE) at pH 4.4 was used to study the concentration dependence of absolute mobility of crotamine. Within amounts ranging from 5-65 micrograms the toxin appeared in at least three n-mer species which were characterized by their geometrical mean radius R and molecular weight Mr estimation. The R and Mr values of crotamine bands were obtained from equations described in the literature and by using standard polypeptides and proteins submitted to the same experimental conditions. When amounts of up to 20 micrograms were assayed by PAGE the bands had a monomer molecular weight value of 4650 and R was 1.08 nm. From 20-35 micrograms the toxin migrated as dimer (Mr 10,000) with an R value of 1.42 nm. However, amounts higher than 35 micrograms crotamine were mostly resolved in a "two-band" pattern with R and Mr values corresponding to higher associated species.
Laboratório de Biofísica Molecular, Instituto de Biociências, UFRGS,Porto Alegre, RS, Brazil.
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Hampe
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Junqueira
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Vozári-Hampe
D002138:Calibration; D003435:Crotalid Venoms / Q000032:analysis* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight
D003435:Crotalid Venoms; C010563:crotamine