The effect of secB on protein folding. A single molecule study

PhD Ceremony: dhr. A.P. Bechtluft, 13.15 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: The effect of secB on protein folding. A single molecule study

Promotor(s): prof.dr. A.J.M. Driessen

Faculty: Mathematics and Natural Sciences

Contact: Philipp Bechtluft, tel. 020-754 7172, e-mail: bechtluft@amolf.nl

The thesis of Philipp Bechtluft deals with a single molecule analysis of the impact of a molecular chaperone, SecB, on the folding of proteins. In this intuitive experimental setup a single protein was immobilized between two plastic beads and mechanically unfolded by optical tweezers. First the unfolding and refolding pathway of the single protein was determined. Next the molecular chaperone SecB was added to the tethered substrate protein allowing for the first time a direct visualization of the effect of a chaperone on folding of the substrate at the single molecule level. The SecB chaperone was shown to bind to the unfolded substrate, whereby this protein was kept in a completely unfolded state. Furthermore, the chaperone prevented aggregation of four substrate proteins that were fused in tandem. These studies provided detailed information about the action of a molecular chaperone both on protein folding as well as on protein aggregation.