In this lecture, Single Molecule Studies of Rad51 and Srs2 will be discussed by Dr. Myong. We first look at the different ways to carry out the single molecule fluorescence detection through colors. The way the signals are monitored from these molecules is through the immobilization of molecules like DNA or protein. Fluorescence Resonance Energy Transfer (FRET) is known as the spectroscopic ruler because it can measure distances by looking at intensity. The force of light which is silanized is used on the slide. The slide is then used to detect molecules which are close to the detection surface which means the molecules that are having an interaction with the substrates. The experimental setup for this procedure is then discussed. Protein Induced Fluorescence Enhancement (PIFE) is then discussed and we see how the protein enhances the fluorescence of the dye. The FRET vs. PIFE is then compared and contrasted. The lecture then moves on to Homologous Recombination which is a means of gene exchange between two chromosomes and a crucial method in which the DNA repairs itself. We then see that Rad51 is a recombinase protein while Srs2 is an anti-recombinase and the properties they exhibit. The lecture then moves on to the formation of Rad51 and the way it forms a filament one monomer at a time. Srs2, the protein, makes a 2-dye distance in a rapid manner in repetition. The Srs2 somehow displaces this repetitive motion on single-stranded DNA. However, the Srs2 movement is fueled and dependant on ATP and without ATP there would be no fluctuation. This Srs2 repetitive motion is then seen to be limited to a finite single-stranded DNA length. The Srs2 preventing the reformation of Rad51 upon clearance is looked at. The monomer Srs2 can remove the Rad51 Filament. The Srs2 clearance is delayed for a stable Rad51 filament. This means that the Srs2 in a way can have its unwinding suppressed by the Rad51. The lecture ends with a summary of the things seen and the comparisons between the FRET, the PIFE, the Rad51, and the Srs2
My research group is focused on the application of sub-wavelength optical phenomena and fabrication methods to the development of novel devices and instrumentation for the life sciences. The group is highly interdisciplinary, with expertise in the areas of microfabrication, nanotechnology, computer simulation, instrumentation, molecular biology, and cell biology. In particular, we are working on biosensors based upon photonic crystal concepts that can either be built from low-cost flexible plastic materials, or integrated with semiconductor-based active devices, such as light sources and photodetectors, for high performance integrated detection systems.
Using a combination of micrometer-scale and nanometer-scale fabrication tools, we are devising novel methods and materials for producing electro-optic devices with nanometer-scale features that can be scaled for low-cost manufacturing. Many of our techniques are geared for compatibility with flexible plastic materials, leading to applications such as low cost disposable sensors, wearable sensors, flexible electronics, and flexible displays. Because our structures manipulate light at a scale that is smaller than an optical wavelength, we rely on computer simulation tools such as Rigorous Coupled Wave Analysis (RCWA) and Finite Difference Time Doman (FDTD) to model, design, and understand optical phenomena within photonic crystals and related devices.
In addition to fabricating devices, our group is also focused on the design, prototyping, and testing of biosensor instrumentation for high sensitivity, portability, and resolution. Advanced instruments enable high resolution imaging of biochemical and cellular interactions with the ability to monitor images of biochemical interactions as a function of time. Using the sensors and instrumentation, we are exploring new applications for optical biosensor technology including protein microarrays, biosensor/mass spectrometry systems, and microfluidics-based assays using nanoliter quantities of reagents. The methods and systems developed in the laboratory are applied in the fields of life science research, drug discovery, diagnostic testing, and environmental monitoring. -From Professor Cunningham's Faculty Profile
Sua obtained her B.S in Molecular Cellular Biology and Ph.D in Nutrition from the University of California, Berkeley. She joined the laboratory of Taekjip Ha at University of Illinois for her postdoctorate training. Sua's enthusiasm for single molecule research was ignited from conducting helicase measurement in the Ha laboratory. Before joining the Bioengineering department as an Assistant professor in 2009, Sua spent two years at the Institute for Genomic Biology where she currently remains an affiliate member as a core faculty of a newly emerging theme "Cellular decision making in cancers."
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