Comparative Crystallographic Analysis of a Non-Methylated to Methylated DNA Hexamer GCCGGC.

Speaker: Christine Nguyen

Abstract: The question of interest in my research is based on why a methylated cytosine of the DNA hexamer GCmCGGC reacts faster with H2O during deamination than the non-methylated hexamer GCCGGC. The importance of this study focuses on the role of methylation in sequence structure determination. Specifically, does the methylated hexamer result in a new and unique structure conformation or does it retain the A-DNA structure con-formation of the non-methylated hexamer. The hypothesis is that methylation of the hexamer will result in a transition or perturbation of the DNA conformation.
I am currently researching the methylated DNA hexamer using the same methods which I have used to study the non-methylated hexamer. These include DNA synthesis and purification, growing crystals, collecting data using the diffractometer, and refining and analyzing the data with the programs X-plor and Xtalview. At this point, my research remains in growing crystals of diffraction quality. My long term goal is to obtain the structure of the methylated DNA hexamer for comparative analysis with the non-methylatd DNA hexamer. Of equal importance, is studying the location and geometry of H2O in the deamination reaction of cytosine. This will reveal the importance of H2O in relation to the biological structure.