Abstract
A generalized phenomenological model is presented for stereospecific recognition between biological receptors and their ligands. We ask what is the distribution of binding constants psi(K) between an arbitrary ligand and members of a large receptor repertoire, such as immunoglobulins or olfactory receptors. For binding surfaces with B potential subsite and S different types of subsite configurations, the number of successful elementary interactions obeys a binomial distribution. The discrete probability function psi(K) is then derived with assumptions on alpha, the free energy contribution per elementary interaction. The functional form of psi(K) may be universal, although the parameter values could vary for different ligand types. An estimate of the parameter values of psi(K) for iodovanillin, an analog of odorants and immunological haptens, is obtained by equilibrium dialysis experiments with nonimmune antibodies. Based on a simple relationship, predicted by the model, between the size of a receptor repertoire and its average maximal affinity toward an arbitrary ligand, the size of the olfactory receptor repertoire (Nolf) is calculated as 300-1000, in very good agreement with recent molecular biological studies. A very similar estimate, Nolf = 500, is independently derived by relating a theoretical distribution of maxima for psi(K) with published human olfactory threshold variations. The present model also has implications to the question of olfactory coding and to the analysis of specific anosmias, genetic deficits in perceiving particular odorants. More generally, the proposed model provides a better understanding of ligand specificity in biological receptors and could help in understanding their evolution.
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Selected References
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- Amoore J. E. Evidence for the chemical olfactory code in man. Ann N Y Acad Sci. 1974 Sep 27;237(0):137–143. doi: 10.1111/j.1749-6632.1974.tb49850.x. [DOI] [PubMed] [Google Scholar]
- Berek C., Milstein C. The dynamic nature of the antibody repertoire. Immunol Rev. 1988 Oct;105:5–26. doi: 10.1111/j.1600-065x.1988.tb00763.x. [DOI] [PubMed] [Google Scholar]
- Bowman J. D., Aladjem F. A method for the determination of heterogeneity of antibodies. J Theor Biol. 1963 May;4(3):242–253. doi: 10.1016/0022-5193(63)90003-1. [DOI] [PubMed] [Google Scholar]
- Buck L., Axel R. A novel multigene family may encode odorant receptors: a molecular basis for odor recognition. Cell. 1991 Apr 5;65(1):175–187. doi: 10.1016/0092-8674(91)90418-x. [DOI] [PubMed] [Google Scholar]
- Davis M. M., Bjorkman P. J. T-cell antigen receptor genes and T-cell recognition. Nature. 1988 Aug 4;334(6181):395–402. doi: 10.1038/334395a0. [DOI] [PubMed] [Google Scholar]
- Gross-Isseroff R., Ophir D., Bartana A., Voet H., Lancet D. Evidence for genetic determination in human twins of olfactory thresholds for a standard odorant. Neurosci Lett. 1992 Jul 6;141(1):115–118. doi: 10.1016/0304-3940(92)90347-a. [DOI] [PubMed] [Google Scholar]
- Karush F. Affinity and the immune response. Ann N Y Acad Sci. 1970 Feb 13;169(1):56–64. doi: 10.1111/j.1749-6632.1970.tb55970.x. [DOI] [PubMed] [Google Scholar]
- Katchalski-Katzir E., Shariv I., Eisenstein M., Friesem A. A., Aflalo C., Vakser I. A. Molecular surface recognition: determination of geometric fit between proteins and their ligands by correlation techniques. Proc Natl Acad Sci U S A. 1992 Mar 15;89(6):2195–2199. doi: 10.1073/pnas.89.6.2195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lancet D. Vertebrate olfactory reception. Annu Rev Neurosci. 1986;9:329–355. doi: 10.1146/annurev.ne.09.030186.001553. [DOI] [PubMed] [Google Scholar]
- NISONOFF A., PRESSMAN D. Heterogeneity of antibody sites in their relative combining affinities for structurally related haptens. J Immunol. 1958 Aug;81(2):126–135. [PubMed] [Google Scholar]
- Nebert D. W., Nelson D. R., Coon M. J., Estabrook R. W., Feyereisen R., Fujii-Kuriyama Y., Gonzalez F. J., Guengerich F. P., Gunsalus I. C., Johnson E. F. The P450 superfamily: update on new sequences, gene mapping, and recommended nomenclature. DNA Cell Biol. 1991 Jan-Feb;10(1):1–14. doi: 10.1089/dna.1991.10.1. [DOI] [PubMed] [Google Scholar]
- Percus J. K., Percus O. E., Perelson A. S. Predicting the size of the T-cell receptor and antibody combining region from consideration of efficient self-nonself discrimination. Proc Natl Acad Sci U S A. 1993 Mar 1;90(5):1691–1695. doi: 10.1073/pnas.90.5.1691. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Perelson A. S., Oster G. F. Theoretical studies of clonal selection: minimal antibody repertoire size and reliability of self-non-self discrimination. J Theor Biol. 1979 Dec 21;81(4):645–670. doi: 10.1016/0022-5193(79)90275-3. [DOI] [PubMed] [Google Scholar]
- Schild D. Principles of odor coding and a neural network for odor discrimination. Biophys J. 1988 Dec;54(6):1001–1011. doi: 10.1016/S0006-3495(88)83038-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Senf W., Menco B. P., Punter P. H., Duyvesteyn P. Determination of odour affinities based on the dose-response relationships of the frog's electro-olfactogram. Experientia. 1980 Feb 15;36(2):213–215. doi: 10.1007/BF01953738. [DOI] [PubMed] [Google Scholar]
- Shepherd G. M., Firestein S. Making scents of olfactory transduction. Curr Biol. 1991 Aug;1(4):204–206. doi: 10.1016/0960-9822(91)90056-3. [DOI] [PubMed] [Google Scholar]
- Weisbuch G. A shape space approach to the dynamics of the immune system. J Theor Biol. 1990 Apr 23;143(4):507–522. doi: 10.1016/s0022-5193(05)80027-x. [DOI] [PubMed] [Google Scholar]
- Wysocki C. J., Beauchamp G. K. Ability to smell androstenone is genetically determined. Proc Natl Acad Sci U S A. 1984 Aug;81(15):4899–4902. doi: 10.1073/pnas.81.15.4899. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yee E. Reconstruction of the antibody affinity distribution from experimental binding data by a minimum cross-entropy procedure. J Theor Biol. 1991 Nov 21;153(2):205–227. doi: 10.1016/s0022-5193(05)80423-0. [DOI] [PubMed] [Google Scholar]
- de Boer R. J., Perelson A. S. Size and connectivity as emergent properties of a developing immune network. J Theor Biol. 1991 Apr 7;149(3):381–424. doi: 10.1016/s0022-5193(05)80313-3. [DOI] [PubMed] [Google Scholar]
