Dresden 2006 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 40: Poster Session II

AKB 40.61: Poster

Mittwoch, 29. März 2006, 16:30–19:30, P3

Characterisation of the affinity improvement of antibody mutants with dynamic force spectroscopy — •Julia Morfill and Kerstin Blank — Lehrstuhl für angewandte Physik, LMU München, Amalienstrasse 54, 80799 München

Many biotechnological and pharmaceutical applications require antibodies with high specificity and affinity. To optimise antibody-antigen interactions, a detailed knowledge of the structure of the binding pocket is useful. We investigated four different mutants of a recombinant antibody fragment with a known crystal structure specific for a peptide with single molecule force spectroscopy. The results of these measurements show a loading rate dependent unbinding force. For the clone with the highest affinity (KD = 5.2 pM) we achieved a spontaneous dissociation rate in the order of 10e-4 1/s and a potential width of 0.9 nm. The clone with the lowest affinity (KD = 2.6 nM) has a similar potential width and a dissociation rate in the order of 10e-3 1/s. Interestingly, the two clones only differ in a few amino acids, which do not directly interact with the antigen. In order to explain the affinity improvement, it is therefore necessary to have a more detailed look at the dynamics of the unbinding process.