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1887

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Volume 86, Issue 1

Oligomeric Structure of Cholera Toxin: Characteristics of the H and L Subunits Free

Abstract

SUMMARY: Structural analysis of cholera toxin by sodium dodecylsulphate polyacrylamide electrophoresis demonstrated two types of non-covalently linked subunits, heavy (H) and light (L), with respective molecular weights of 28000 and 8000 to 9000. The H:L protein ratio was 1:2, indicating that the toxin of molecular weight 84000 consists of 1 H and 6 or 7 L subunits, linked into an aggregate with non-covalent bonds. Choleragenoid toxoid, a natural toxin derivative, contained only the L subunits of the toxin. Reduction and alkylation cleaved the H but not the L sub-unit. The specific cleavage of the H subunit by reduction appeared to yield identical half-molecules; the smaller peptide seemed to originate from non-specific degradation. The H subunit also differed from L subunits by having a higher affinity for labelling with radioactive iodine and by precipitating below pH 3·5.

In immunodiffusion studies the toxin possessed antigenic determinants shared with the toxoid as well as toxin-specific determinants. Comparative analyses with purified subunit preparations revealed that the toxoid-shared determinants reside in the L-type of subunit and the toxin-specific ones in the H subunit.

By precipitation-in-gel, binding to ganglioside-coated tubes, and sodium dodecyl sulphate polyacrylamide electrophoresis it was demonstrated that the ability of toxin to attach to the apparent receptor ganglioside, G is similar to that of choleragenoid toxoid, and is due to the G-binding ability of the L subunits. The toxin H subunit did not react with the G ganglioside.

The results support our previous structural model for cholera toxin, and explain the antigenic and receptor-binding properties of the toxin in terms of component subunits.

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© Society for Gerenal Microbiology 1975
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1975-01-01
2025-04-28
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References

  1. Craig J. P. 1965; A permeability factor (toxin) found in cholera stools and culture filtrates and its neutralization by convalescent cholera sera. Nature; London: 207614–616
     [Google Scholar]
  2. Cuatrecasas P. 1973a; Vibrio cholerae choleragenoid. Mechanism of inhibition of cholera toxin action. Biochemistry 12:3577–3581
     [Google Scholar]
  3. Cuatrecasas P. 1973b; Gangliosides and membrane receptors for cholera toxin. Biochemistry 12:3558–3566
     [Google Scholar]
  4. Cuatrecasas P., Parikh I., Hollenberg D. 1973; Affinity chromatography and structural analysis of Vibrio cholerae enterotoxin-ganglioside agarose and the biological effects of ganglioside-containing soluble polymers. Biochemistry 12:4253–4264
     [Google Scholar]
  5. Finkelstein R. A., Lospalluto J. J. 1969; Pathogenesis of experimental cholera. Preparation and isolation of choleragen and choleragenoid. Journal of Experimental Medicine 130:185–202
     [Google Scholar]
  6. Finkelstein R. A., Lospalluto J. J. 1970; Production of highly purified choleragen and choleragenoid. Journal of Infectious Diseases 121:S63–72
     [Google Scholar]
  7. Griffith I. P. 1972; The effect of cross-links on the mobility of proteins in dodecyl sulphate-polyacrylamide gels. Biochemical Journal 126:553–560
     [Google Scholar]
  8. Van Heyningen S. 1974; Cholera toxin: interaction of subunits with ganglioside GM1 . Science; New York: 183656–657
     [Google Scholar]
  9. Holmgren J. 1973a; Comparison of the tissue receptors for Vibrio cholerae and Escherichia coli enterotoxins by means of ganeliosides and natural cholera toxoid. Infection and Immunity 8:851–859
     [Google Scholar]
  10. Holmgren J. 1973b; Immunologic and receptor-binding properties of cholera toxin and its subunits. In Proceedings of the 9th Joint Cholera Research Conference U.S. Department of State Publication; 8762196–213
     [Google Scholar]
  11. Holmgren J., Lindholm L., Lönnroth I. 1974a; Interactions of cholera toxin and toxin derivatives with lymphocytes. I. Binding properties and interference with lectin-induced cellular stimulation. Journal of Experimental Medicine 139:801–819
     [Google Scholar]
  12. Holmgren J., Lönnroth I., Ouchterlony Ö. 1971; Immunochemical studies of two cholera toxin-containing preparations of Vibrio cholerae. Infection and Immunity 3:747–755
     [Google Scholar]
  13. Holgren J., Lönnroth I., Ouchterlony Ö., Svennerholm A. -M. 1972; Studies on cholera toxins. Journal of General Microbiology 73:xxix
     [Google Scholar]
  14. Holmgren J., Lönnroth I., Svennerholm L. 1973a; Fixation and inactivation of cholera toxin by GM1 ganglioside. Scandinavian Journal of Infectious Diseases 5:77–78
     [Google Scholar]
  15. Holmgren J., Lönnroth I., Svennerholm L. 1973b; Tissue receptor for choleraexotoxin:postulated structure from studies with GM1 gangliosideand related glycolipids. Infection and Immunity 8:208–214
     [Google Scholar]
  16. Holmgren J., Månsson J.-E., Svennerholm L. 1974b; Tissue receptor for choleraexotoxin:structural requirements of GM1 ganglioside in toxin binding and inactivation. Medical Biology 52:229–233
     [Google Scholar]
  17. Holmgren J., Svennerholm A.-M. 1973; Enzyme-linked immunosorbent assays for cholera serology. Infection and Immunity 7:759–763
     [Google Scholar]
  18. Hunter W. M., Greenwood F. C. 1962; Preparation of iodine-131 labelled human growth hormone of high specific activity. Nature; London: 194495–497
     [Google Scholar]
  19. King C. A., Van Heyningen W. E. 1973; Deactivation of cholera toxin by a sialidase-resistant monosialosylganglioside. Journal of Infectious Diseases 127:639–647
     [Google Scholar]
  20. Lospalluto J. J., Finkelstein R. A. 1972; Chemical and physical properties of cholera exo-enterotoxin (choleragen) and its spontaneously formed toxoid (choleragenoid). Biochemica et biophysica acta 257:158–166
     [Google Scholar]
  21. Lönnroth I., Holmgren J. 1973; Subunit structure of cholera toxin. Journal of General Microbiology 76:417–427
     [Google Scholar]
  22. Peterson J. W., Lospalluto J. J., Finkelstein R. A. 1972; Localization of cholera toxin in vivo. Journal of Infectious Diseases 126:617–628
     [Google Scholar]
  23. Pierce N. F. 1973; Differential inhibitory effects of cholera toxoid and ganglioside on the enterotoxins of Vibrio cholerae and Escherichia coli. Journal of Experimental Medicine 137:1009–1023
     [Google Scholar]
  24. Richardson S. H., Evans D. G., Feeley J. C. 1970; Biochemistry of Vibrio cholerae virulence.I. Purification and biochemical properties of PF/cholera enterotoxin. Infection and Immunity 1:546–554
     [Google Scholar]
  25. Svennerholm L. 1972; Ganglioside isolation. In Methods in Carbohydrate Chemistry 6 pp. 464–474 Whistler R. L., Bemiller J. N. Edited by New York: Academic Press;
     [Google Scholar]
/content/journal/micro/10.1099/00221287-86-1-49
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Oligomeric Structure of Cholera Toxin: Characteristics of the H and L Subunits
Microbiology 86, 49 (1975); https://doi.org/10.1099/00221287-86-1-49
/content/journal/micro/10.1099/00221287-86-1-49
/content/journal/micro/10.1099/00221287-86-1-49
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