Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 13: DNA/RNA and Related Enzymes

BP 13.4: Talk

Wednesday, March 28, 2012, 10:30–10:45, H 1058

The binding of monoclonal antibodies and tau-peptides - how two binding sites add up to form a stable specific bond — •Carolin Wagner, David Singer, Tim Stangner, Christof Gutsche, Olaf Ueberschär, Ralf Hoffmann, and Friedrich Kremer — Leipzig University, Leipzig, Germany

Optical tweezers-assisted dynamic force spectroscopy (DFS) is employed to investigate specific receptor/ligand interactions on the level of single binding events [1]. Here, the specific binding of the anti-human tau monoclonal antibody (mAb), HPT-101, to synthetic tau-peptides is analyzed. Amongst others, the massive accumulation of tangles that mainly consist of hyperphosphorylated tau-proteins is characteristic for Alzheimer*s disease. The sorts of tau-peptides, which are used in this study, contain either one phosphorylation, at Thr231 and Ser235, respectively, or they are phosphorylated at both sites. From measurements using ELISA it is known, that the HPT-101 binds only specifically to the double-phosphorylated tau-peptide. The results obtained by DFS show, that HPT-101 binds also to each sort of the mono-phosphorylated peptides. By analyzing the measured rupture-force distributions characteristic parameters like the lifetime of the bond without force t0, the characteristic length xts and the free energy of activation Delta G are determined for all interactions. Thereby it can be shown how the attachments of HPT-101 with the mono-phosphorylated peptides add up in the case of the double-phosphorylated peptide in order to form the strong specific binding.

[1] C. Wagner et al., Soft Matter, 2011, 7 (9), 4370 - 4378