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AKB: Biologische Physik

AKB 200: Poster Session II

AKB 200.50: Poster

Dienstag, 8. März 2005, 17:00–19:00, Poster TU C

Fluorescence spectroscopy of DNA nanodevices — •Andreas Reuter and Friedrich C. Simmel — CeNs und Department für Physik, Geschwister-Scholl-Platz 1, 80539 München

DNA tweezers consist of three branches of single stranded DNA, one of which is labelled with a fluorescence resonance energy transfer (FRET) pair. The three single strands form two double-stranded arms of 18 base pairs or roughly 6.1 nm length connected by a short hinge. The two duplex arms can be pulled together by the addition of a fourth single stranded DNA. In this case the dyes are in close proximity and FRET is very efficient. For the open configuration of the tweezers the average distance between the dyes was determined to be around 6 nm which corresponds to a mean opening angle between the duplex arms of 60^∘. However this value represents an average value over many possible configurations.

We perform single pair FRET experiments on three different configurations of the tweezers: fully stretched, where the dyes are separated by 40 base pairs, opened and closed. The width of the distribution of FRET efficiencies contains important information about the flexibility of the DNA nanodevice.