Voelcker Academy

Research Symposium 2012


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Blanca Hernandez Uribe

Biophysical Studies of DNA anisotropy in the solution phase

Blanca Hernandez Uribe

Mentor(s): Borries Demeler PhD

The goal of our studies will be to study the effects of various solution conditions on the conformational variation of DNA. We will use biophysical techniques such as analytical ultracentrifugation (AUC) and dynamic laser light scattering (DLS) to precisely measure the anisotropy of DNA under these different solution conditions. We will accomplish this by carefully determining the sedimentation and diffusion properties, and molecular densities for a series of differently sized linear double-stranded DNA fragments as a function of DNA, salt and SybrGreen (a fluorescent dye) concentration, as well as rotor speed, which modulates pressure on the molecules. We will also determine the limits of resolution provided by the AUC method. Preliminary results suggest that increasing the NaCl concentration reduces anisotropy for a given DNA fragment size, and that anisotropy increases with increasing molecular size. Previous studies also have shown that variation of rotor speed can affect the density of DNA by changing the hydration as a function of pressure. Our study will result in a high-resolution method to characterize DNA anisotropy under a variety of solution conditions which will ultimately help our understanding of DNA conformation, and its role in the structure and function of DNA.