title: Protein-chemical analysis of pertussis toxin reveals homology between the subunits S2 and S3, between S1 and the A chains of enterotoxins of Vibrio cholerae and Escherichia coli and identifies S2 as the haptoglobin-binding subunit.
abstract: The purified toxin of Bordetella pertussis was dissociated in 5 M urea in the presence of immobilized haptoglobin. The toxin was dissociated in free S1, free S5 and the free complexes S2-S4 and S3-S4, with S2-S4 as the only haptoglobin-binding moiety, identifying S2 as the haptoglobin-binding protein. Partial NH2-terminal amino acid sequences were obtained from the dissimilar toxin subunits, after separation by SDS-polyacrylamide gel electrophoresis followed by electroblotting onto polybrene-coated glass-fiber sheets. The sequences reveal extensive homology of the N-terminal portions of the constitutive subunits S2 and S3 and between S1 and the enterotoxin A chains of Vibrio cholerae and Escherichia coli.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004768:Enterotoxins; D004926:Escherichia coli / Q000378:metabolism; D006242:Haptoglobins; D037342:Pertussis Toxin; D012689:Sequence Homology, Nucleic Acid; D014734:Vibrio cholerae / Q000378:metabolism; D010566:Virulence Factors, Bordetella
chemical_list: D002352:Carrier Proteins; D004768:Enterotoxins; D006242:Haptoglobins; D010566:Virulence Factors, Bordetella; C037420:stN protein, Vibrio cholerae; D037342:Pertussis Toxin