Calander Home 2001-2002 2002-2003 June 3 - Lindsey Hillesheim he fluorescent fluctuations of single molecules: Probingprotein-protein interactions with non-ideal detectors. Date: June 3 Time: Noon to 1 Place: BSBE 6-101 Lindsey Hillesheim, graduate student in the Mueller lab (physics) will present: The fluorescent fluctuations of single molecules: Probingprotein-protein interactions with non-ideal detectors. Fluorescence fluctuation spectroscopy (FFS) and photon countinghistogram (PCH) analysis are powerful tools for studying bio-molecules because information about dynamic processes and heterogeneity are determinedfrom signal fluctuations with single molecule sensitivity. The informationis extracted from the raw data by statistical methods and it is crucial to understand the influence of instrumental parameters on signal statistics in order to correctly interpret the experimental data. Here we focus on the influence of the photo-detector on the statistics of PCH. The influence of two non-ideal detector effects, dead-time and afterpulsing, on the distribution of photon counts will be discussed. Weexperimentally determined the dead-time and afterpulse probability for our detectorsand developed algorithms to correct for these effects in 1D PCH. These corrections are crucial for understanding titration and dilution experiments on biological systems. One such system, that we have begun working with, is the aggregation of the beta-Amyloid protein associated with Alzheimer's disease. The talk will focus on the basic technique we use (FluorescenceFluctuation Spectroscopy) and then I will talk about what I've been working on (correcting for non-ideal detector effects on the data) and where I'llbe going with it (beta-amyloid proteins). I'll probably wrap up the talk with just a little bit about what other people in the lab are doing.