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Effects of ganglioside GM1 on the thermotropic behavior of cholera toxin B subunit

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The B, or binding, subunit of cholera enterotoxin forms a pentameric ring structure in the intact toxin, and also when the subunit is isolated from the A subunit. The thermal denaturation of the B subunit ring was examined by differential scanning calorimetry in the presence and absence of ganglioside GM1, its natural ‘receptor’. In the absence of ganglioside an irreversible endotherm was observed with maximal excess apparent heat capacity, Cmax, at 74.6° C. When the ganglioside was added in increasing amounts, multiple transitions were observed at higher temperatures, the most prominent having a Cmax at 90.8° C. At high ganglioside concentrations, the 74.6° C transition was not observed. In addition to the thermodynamic results a model is proposed for the interaction of GM1 and B subunit pentamer. This model is derived independently of the calorimetric results (but is consistent with such data) and is based upon considerations of the geometry of the GM1 micelle-B subunit pentamer.

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Mr :

molecular weight in daltons

GM1 :

H3Neu-AcGgOse4Cer* = Galβl → 3Ga1NAcβ1 → 4Gal-[3 ←- 2αNeuAc]β1 → 4Glcβ1 → 1Cer (asterisked form follows the recommendations of the IUPACIUB Commission on Biochemical Nomenclature, Ref. 3)


molar ratio of GM1 to B monomer


differential scanning calorimetry

Cmax :

excess apparent heat capacity

Cmax :

maximal value of Cex

tm :

temperature (° C) at Cex = Cmax

Δt1/2 :

peak width in °C at Cex = Cmax/2

ΔHcal :

calorimetric enthalpy

ΔC p d :

van't Hoff enthalpy

ΔC p d :

change in specific heat accompanying denaturation


  1. 1.

    Gill DM: Adv Cycl Nucl Res 8:85–118, 1977.

  2. 2.

    Duffy LK, Peterson JW, Kurosky A: J Biol Chem 256:12252–12256, 1981.

  3. 3.

    IUPAC-IUB Commission on Biochemical Nomenclature: Lipids 12:455–468, 1977.

  4. 4.

    Sillerud LO, Prestegard JH, Yu RK, Konigsberg WH, Schafer DE: J Biol Chem 256:1094–1097, 1981.

  5. 5.

    Schafer DE, Thakur AK: Cell Biophys 4:25–40, 1982.

  6. 6.

    Finkelstein RA: CRC Crit Rev Microbiol 24:553–623, 1973.

  7. 7.

    Sillerud LO, Prestegard JH, Yu RK, Schafer DE, Konigsberg WH: Biochemistry 17:2619–2628, 1978.

  8. 8.

    Ando S, Chang N-C, Yu RK: Anal Biochem 89:437–450, 1978.

  9. 9.

    Svennerholm L: Biochim Biophys Acta 24:604–611, 1957.

  10. 10.

    Privalov PL, Plotnikov VV, Filimonov VV: J Chem Thermodyn 7:41–47, 1975.

  11. 11.

    Corti M, Degiorgio V, Ghidoni R, Sonnino S, Tettamanti G: Chem Phys Lipids 26:225–238, 1980.

  12. 12.

    Dwyer JD, Bloomfield VA: Biopolymers 20:2323–2336, 1981.

  13. 13.

    Dwyer JD, Bloomfield VA; Biochemistry 21:3227–3231, 1982.

  14. 14.

    Curatolo W, Small DM, Shipley GG: Biochim Biophys Acta 468:11–20, 1977.

  15. 15.

    Mabrey S, Sturtevant JM: In: Korn ED (ed), Methods in Membrane Biology, Vol 9. Plenum Press, New York, 1978, pp 237–279.

  16. 16.

    Dunaway M, Manly SP, Matthews KS: J Biol Chem 254:3348–3353, 1979.

  17. 17.

    Fukada H, Quiocho F, Sturtevant J: J Biol Chem 258: 13193–13198, 1983.

  18. 18.

    Takahashi K, Sturtevant JM: Biochemistry 20:6185–6190, 1981.

  19. 19.

    Spink CH, Müller K, Sturtevant JM: Biochemistry 24:6598–6605, 1982

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Correspondence to David E. Schafer.

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Dalziel, A.W., Lipka, G., Chowdhry, B.Z. et al. Effects of ganglioside GM1 on the thermotropic behavior of cholera toxin B subunit. Mol Cell Biochem 63, 83–91 (1984). https://doi.org/10.1007/BF00230165

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  • binding
  • calorimetry
  • cholera toxin B subunit
  • denaturation
  • ganglioside GM1
  • thermodynamics