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SYBP: Biologie und Physik

SYBP 3: POSTER

SYBP 3.15: Poster

Thursday, March 30, 2000, 15:00–18:00, D

Statistical model for antibody-antigen binding — •Stefan Katletz and Urbaan M. Titulaer — Institut für Theoretische Physik, Universität Linz, Altenbergerstr. 69, A-4040 Linz, Austria

We discuss a statistical model for antibody-antigen binding. The two macromolecules are assumed to be linked by a number of relatively weak bonds (or groups of correlated bonds) that are assumed to open and close statistically. We use the model for a preliminary analysis of experiments performed in the Institute for Biophysics at the Johannes Kepler University. In these experiments the two molecules are brought into contact using an atomic force microscope; then a prescribed time dependent force is applied to the bond and the distribution of times needed to pull the molecules completely apart is measured. This quantity is calculated with our model; its dependence on the model parameters (binding free energies, number of groups of correlated elementary bonds, rate of change of the pulling force) is determined. The influence of cooperativity on the binding strength is also considered.