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CPP: Chemische Physik und Polymerphysik

CPP 25: Biological systems I

CPP 25.1: Vortrag

Dienstag, 8. März 2005, 14:00–14:15, TU C230

Perspectives for variable-temperature investigations of single-protein dynamics — •Florian Kulzer, Rob Zondervan, Joris Berkhout, and Michel Orrit — Molecular Nano–Optics and Spins (MoNOS), Huygens Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands

The conformational dynamics of proteins, a key issue in molecular biology, are characterized by the existence of a complex energy landscape, leading to a potentially huge number of possible folding routes for a given protein. This presents the experimenter with the challenge of following simultaneous rapid transitions between many different conformational states. Optical experiments on individual protein molecules naturally avoid the difficulties associated with unsynchronized ensembles, but their scope is severely limited by photoblinking and photobleaching of the probe chromophores (reversible and irreversible transitions to non-emissive states).

Our contribution will present our efforts to develop a novel approach to overcome some of these inherent limitations of “conventional” single-molecule experiments on biological systems. Our method tries to avoid the problems with photoblinking and photobleaching by relying on rapid thermal cycling of a microscopic sample. This way the long-time conformational evolution of single proteins could be split up in successively frozen structural “snapshots,” which could be subjected to detailed probing at low temperatures. We will present our recent results showing that we have managed to implement the rapid thermal cycling procedure and discuss the perspectives for further investigations.