Kinetics of Antibody-Hapten Interactions

Pecht, Israel; Lancet, Doron

doi:10.1007/978-3-642-81117-3_9

Cited by 49 publications

(26 citation statements)

References 39 publications

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“…This result, together with their remarkably slow values, which are at least two orders of magnitude slower than those expected for diffusion controlled processes (23), clearly suggest that the association process involves crossing Table 1. Parameters derived by fitting of the observed association and dissociation time courses of the sT1 TCR-H-2K d -pPbS AB interaction at 25°C shown in Fig.…”

mentioning

confidence: 66%

“…We found that this model fits the simulated data when k 12 Ͻ Ͻ k 21 , and therefore the free TCR exists mostly in the binding inactive conformation. This binding conformer readily associates with the ligand at close to the diffusion-limited rate k 23 . Hence, a conformational transition within the TCRbinding site controls the overall association time course and its rate would then be independent of the ligand structure.…”

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confidence: 99%

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T cell receptor-ligand interactions: A conformational preequilibrium or an induced fit

Gakamsky

Luescher

Pecht

2004

Proc. Natl. Acad. Sci. U.S.A.

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Kinetic parameters of T cell receptor (TCR) interactions with its ligand have been proposed to control T cell activation. Analysis of kinetic data obtained has so far produced conflicting insights; here, we offer a consideration of this problem. As a model system, association and dissociation of a soluble TCR (sT1) and its specific ligand, an azidobenzoic acid derivative of the peptide SYIPSAEK-(ABA)I (residues 252-260 from Plasmodium berghei circumsporozoite protein), bound to class I MHC H-2K d -encoded molecule (MHCp) were studied by surface plasmon resonance. The association time courses exhibited biphasic patterns. The fast and dominant phase was assigned to ligand association with the major fraction of TCR molecules, whereas the slow component was attributed to the presence of traces of TCR dimers. The association rate constant derived for the fast phase, assuming a reversible, single-step reaction mechanism, was relatively slow and markedly temperature-dependent, decreasing from 7.0 ؋ 10 3 at 25°C to 1.8 ؋ 10 2 M ؊1 ⅐s ؊1 at 4°C. Hence, it is suggested that these observed slow rate constants are the result of unresolved elementary steps of the process. Indeed, our analysis of the kinetic data shows that the time courses of TCR-MHCp interaction fit well to two different, yet closely related mechanisms, where an induced fit or a preequilibrium of two unbound TCR conformers are operational. These mechanisms may provide a rationale for the reported conformational flexibility of the TCR and its unusual ligand recognition properties, which combine high specificity with considerable crossreactivity.

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confidence: 66%

mentioning

confidence: 99%

T cell receptor-ligand interactions: A conformational preequilibrium or an induced fit

Gakamsky

Luescher

Pecht

2004

Proc. Natl. Acad. Sci. U.S.A.

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“…In the above relation, AG is the free energy change of reaction, AH and AS are the enthalpy and entropy of reaction, respectively, and R is the gas constant. Using reasonable values for these parameters developed for antibody-hapten interactions (Pecht and Lancet, 1977), a change in temperature from 370 to 4°C may lead to a maximum 18-fold enhancement ofthe affinity, although typical increases may be closer to 5-fold. Thus, the effect of temperature on receptor-ligand and receptor-talin association can be investigated through changes in the appropriate binding affinity.…”

Section: Appendix Cmentioning

confidence: 99%

A theoretical analysis for the effect of focal contact formation on cell-substrate attachment strength

Ward

Hammer

1993

Biophysical Journal

143

106

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For many cell types, growth, differentiation, and motility are dependent on receptor-mediated adhesion to ligand-coated surfaces. Focal contacts are strong, specialized, adhesive connections between cell and substrate in which receptors aggregate and connect extracellular ligand to intracellular cytoskeletal molecules. In this paper, we present a mathematical model to examine how focal contact formation affects cellular adhesive strength. To calculate adhesive strength with and without focal contacts, we use a one-dimensional tape peeling analysis to determine the critical tension necessary to peel the membrane. Receptor-ligand bonds are modeled as adhesive springs. In the absence of focal contacts, we derive analytic expressions for the critical tension at low and high ligand densities and show how membrane morphology affects adhesion. Then, focal contacts are modeled as cytoplasmic nucleation centers which bind adhesion receptors. The extent of adhesive strengthening upon focal contact formation depends on the elastic rigidity of the cytoskeletal connections, which determines the structural integrity of the focal contact itself. We consider two limits to this elasticity, very weak and rigid. Rigid cytoskeletal connections give much greater attachment strengths. The dependence of attachment strength on measurable model parameters is quite different in these two limits, which suggests focal contact structure might be deduced from properly performed adhesion experiments. Finally, we compare our model to the adhesive strengthening response reported for glioma cell adhesion to fibronectin (Lotz et al., 1989. J. Cell Biol. 109:1795-1805). Our model successfully predicts the observed detachment forces at 4 degrees C and yields values for the number of fibronectin receptors per glioma cell and the density of cytoskeletal connection molecules (talin) involved in receptor clusters which are consistent with measurements for other cell types. Comparison of the model with data at 37 degrees C suggests that while cytoskeletal cross-linking and clustering of fibronectin receptors significantly increases adhesion strength, specific glioma cell-substratum attachment sites possess little mechanical rigidity and detach through a peeling mechanism, consistent with the view that these sites of < or = 15 nm cell-substrate separation are precursors to fully formed, elastically rigid focal contacts.

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“…Such changes may not be resolved by static binding measurements because the Fab usually binds only one hapten per two chains (8,28). However, kinetic measurements have resolved hapten-induced conformational transitions in an increasing number of different homogeneous immunoglobulins (28)(29)(30).…”

Section: Resultsmentioning

confidence: 99%

Effect of interchain disulfide bond on hapten binding properties of light chain dimer of protein 315.

Zidovetski¹,

Licht²,

Pecht³

1979

Proc. Natl. Acad. Sci. U.S.A.

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The hapten binding characteristics of the covalent light chain dimer, derived from the murine IgA secreted by plasmacytoma MOPC-315, to two nitroaromatic compounds, epsilon-N-(2,4-dinitrophenyl)-L-lysine and 4-(alpha-N-alanine)-m-nitrobenz-2-oxa-1,3-diazole, were investigated by differential spectroscopic titrations. The binding curves for both haptens were found to display sigmoidity similar to that reported earlier for the reduced and alkylated dimer held together by noncovalent bonds only. However, the presence of the interchain disulfide bond in the covalent dimer was found to cause marked changes in its binding properties. The data, like those obtained for the noncovalent dimer, fit the allosteric model of Monod, Wyman, and Changeux in which binding of the first hapten to the dimer causes a conversion of both sites of the protein molecule from a lower to a higher affinity conformation. However, the binding parameters show that both the affinity and the positive cooperativity in the interaction between haptens and the covalent dimer are significantly enhanced. The differences in the parameters of the binding and of the allosteric transition caused by the presence of the interchain disulfide bond demonstrate the existence of longitudinal interactions in immunoglobulin derivatives. These properties of the light chain dimer make it a potential model for the receptors present on thymus-derived lymphocytes.

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Kinetics of Antibody-Hapten Interactions

Cited by 49 publications

References 39 publications

T cell receptor-ligand interactions: A conformational preequilibrium or an induced fit

T cell receptor-ligand interactions: A conformational preequilibrium or an induced fit

A theoretical analysis for the effect of focal contact formation on cell-substrate attachment strength

Effect of interchain disulfide bond on hapten binding properties of light chain dimer of protein 315.

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