Regensburg 2010 – scientific programme

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BP: Fachverband Biologische Physik

BP 7: Posters: Biological Machines, Motor Proteins

BP 7.2: Poster

Monday, March 22, 2010, 17:15–20:00, Poster B1

Monitoring a single Sec translocase complex in an anti-Brownian electrokinetic (ABEL) trap — •Torsten Rendler¹, Stefan Ernst¹, Karin Seyfert¹, Andreas Kuhn², and Michael Börsch¹ — ¹3. Physikalisches Institut, Pfaffenwaldring 57, 70569 Stuttgart, Germany — ²Institut für Mikrobiologie und Molekularbiologie, Universität Hohenheim, Germany

Translocation of polypeptides in E. coli cells is catalysed by the membrane protein complex SecAYEG. This process is powered by ATP (adenosine triphosphate) hydrolysis of the SecA motor component. To investigate the translocation process, SecAYEG is reconstituted into lipid vesicles and the conformational changes during polypeptide transport are monitored by internal fluorescence resonance energy transfer (FRET). Therefore, the different SecAYEG subunits were labeled with various fluorescent markers. Previous confocal measurements of single translocases in solution suffered from the limited observation time due to Brownian motion. To increase the observation time we combined a confocal setup for FRET measurements with an anti-Brownian electrokinetic (ABEL) trap. The ABEL-trap was developed by A.E. Cohen (Harvard) and W.E. Moerner (Stanford) and is based on an active feedback mechanism consisting of a EMCCD camera to locate the complex and electrodes to apply an electrical field across the trapping region. We present preliminary FRET data of a single translocases held in solution by the ABEL-trap.