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. 1971 Nov;68(11):2730–2733. doi: 10.1073/pnas.68.11.2730

Homotropic Cooperative Binding of the First Component of Guinea Pig Complement to Rabbit IgG-Erythrocyte Complexes: A Possible Allosteric Effect*

James J Thompson 1, Louis G Hoffmann 1
PMCID: PMC389511  PMID: 5288251

Abstract

Binding of the activated first component of guinea pig complement to immune complexes formed between dinitrophenylated erythrocytes and rabbit IgG antibody to 2,4-dinitrophenylhapten has been studied quantitatively. Cooperative binding was observed; it in volves no interactions between the domains on the erythrocyte surface that bind the activated first component of complement, or between the activated complement molecules in solution. By curve-fitting methods, we find that the data are consistent with an allosteric model, which assumes 10 binding sites per domain, a low allosteric equilibrium constant, and virtually exclusive binding to one of the isomers.

Keywords: binding sites; 2,4-dinitrophenol; sensitized erythrocytes; binding domain

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Borsos T., Rapp H. J. Hemolysin titration based on fixation of the activated first component of complement: evidence that one molecule of hemolysin suffices to sensitize an erythrocyte. J Immunol. 1965 Sep;95(3):559–566. [PubMed] [Google Scholar]
  2. Cathou R. E., Kulczycki A., Jr, Haber E. Structural features of gamma-immunoglobulin, antibody, and their fragments. Circular dichroism studies. Biochemistry. 1968 Nov;7(11):3958–3964. doi: 10.1021/bi00851a024. [DOI] [PubMed] [Google Scholar]
  3. Changeux J. P., Rubin M. M. Allosteric interactions in aspartate transcarbamylase. 3. Interpretation of experimental data in terms of the model of Monod, Wyman, and Changeux. Biochemistry. 1968 Feb;7(2):553–561. doi: 10.1021/bi00842a601. [DOI] [PubMed] [Google Scholar]
  4. Colten H. R., Borsos T., Rapp H. J. Antigenic relationships between the first component (Cl) of human and guinea pig complement. J Immunol. 1970 May;104(5):1048–1051. [PubMed] [Google Scholar]
  5. Green N. M. Electron microscopy of the immunoglobulins. Adv Immunol. 1969;11:1–30. doi: 10.1016/s0065-2776(08)60476-9. [DOI] [PubMed] [Google Scholar]
  6. Hoffmann L. G. Solubility chromatography of serum proteins. I. Isolation of the first component of complement from guinea pig serum by solubility chromatography at low ionic strength. J Chromatogr. 1969 Mar 11;40(1):39–52. doi: 10.1016/s0021-9673(01)96616-6. [DOI] [PubMed] [Google Scholar]
  7. Hoffmann L. G. Statistical evaluation of reaction mechanisms in immune hemolysis. II. The kinetics of release of 86rubidium and hemoglobin from erythrocytes damaged by antibody and complement. Immunochemistry. 1969 Mar;6(2):309–325. doi: 10.1016/0019-2791(69)90167-0. [DOI] [PubMed] [Google Scholar]
  8. Ishizaka T., Tada T., Ishizaka K. Fixation of C' and C'la by rabbit gamma-G- and gamma-M-antibodies with particulate and soluble antigens. J Immunol. 1968 Jun;100(6):1145–1153. [PubMed] [Google Scholar]
  9. MONOD J., WYMAN J., CHANGEUX J. P. ON THE NATURE OF ALLOSTERIC TRANSITIONS: A PLAUSIBLE MODEL. J Mol Biol. 1965 May;12:88–118. doi: 10.1016/s0022-2836(65)80285-6. [DOI] [PubMed] [Google Scholar]
  10. Small P. A., Jr, Lamm M. E. Polypeptide chain structure of rabbit immunoglobulins. I. gamma-G-immunoglobulin. Biochemistry. 1966 Jan;5(1):259–267. doi: 10.1021/bi00865a034. [DOI] [PubMed] [Google Scholar]

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