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BP: Fachverband Biologische Physik

BP 16: Poster Session I

BP 16.51: Poster

Dienstag, 27. März 2007, 17:00–19:30, Poster D

Single Molecule Unzipping of Coiled-Coils: The role of neck/hinge interactions for the regulaton of fungal kinesins — •Elisabeth Wasner, Thomas Bornschlögl, and Matthias Rief — Physik Departement E22, Technische Universität München, James-Franck-Straße, 85748 Garching, Germany

A model for the regulation of motor activity in fungal kinesins suggests important amino acid interactions between the hinge and the neck coiled-coil. The hinge sequence follows the neck and shows no specific tertiary structure. It contains an aromatic tryptophan that is strongly conserved among fungal kinesins.

In this AFM experiment, we try to answer the following question: Does the hinge contribute to the stability of the neck in fungal kinesins?

For this reason, three similar proteins were constructed: All of them contain ddFLN 1-5 domains, a well-investigated leucine zipper (based on GCN4-p1) followed by the Neurospora crassa kinesin neck. These constructs dimerize and are crosslinked by a cysteine that replaces the last d-position of the neck coiled-coil. Two of the constructs additionally contain the hinge - in one of it, the hydrophobic tryptophan has been replaced by a hydrophilic glutamine.

The corresponding protein unfolding and refolding force-extension curves can be interpreted by an equilibrium model und therefore the stability profile along the coiled-coil can be read off.