title: Purification and some properties of a lethal toxic fragment of staphylococcal alpha-toxin by tryptic digestion.
abstract: Purified staphylococcal alpha-toxin (molecular weight approximately 36,000) was mildly digested with trypsin, yielding two components by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A fast-moving component (molecular weight 17,000 +/- 5%) which is relatively resistant to tryptic digestion and a slow-moving component (molecular weight 20,000 +/- 5%) which tends to aggregate. The fast-moving component was highly purified by means of combined procedures of column chromatography on Sephadex G-200 with zone electrophoresis on starch. The purified fast-moving component retained a high degree of lethal toxicity for mouse but lacked hemolytic and dermonecrotic activities, whereas the slow-moving component proved to be a nontoxic polypeptide. The lethal toxic fragment was antigenically active showing partial immunological identity with the parent alpha-toxin and stimulated the formation of antibodies capable of neutralizing the lethal action of alpha-toxin in vivo. Some physical properties and the amino acid composition of the purified lethal toxic fragment have been compared with those of native alpha-toxin.
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis* / Q000302:isolation & purification / Q000633:toxicity; D055598:Chemical Phenomena; D002621:Chemistry; D007928:Lethal Dose 50; D051379:Mice; D008970:Molecular Weight; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000302:isolation & purification* / Q000633:toxicity; D011817:Rabbits; D013210:Staphylococcus; D014357:Trypsin
chemical_list: D001427:Bacterial Toxins; D010446:Peptide Fragments; D014357:Trypsin