Melvin Calvin Lecture in Organic Chemistry: DNA-mediated Signaling

Seminar | February 20 | 11 a.m.-12 p.m. | 120 Latimer Hall

 Prof. Jacqueline Barton, Division of Chemistry and Chemical Engineering, Caltech

 College of Chemistry

Many experiments have now shown that double helical DNA can serve as a conduit for efficient redox chemistry over long molecular distances. This chemistry is exquisitely sensitive to perturbations in the DNA base stack, such as arise with base mismatches, lesions, and protein binding. We have now been exploring how this chemistry may be used within the cell for long range signaling. Increasingly, 4Fe-4S clusters are being found in DNA-binding proteins involved in genome maintenance. These 4Fe-4S clusters, common redox cofactors, are associated not only with repair proteins but also DNA polymerases and primase. Studies are described to characterize DNA–mediated charge transport by these metalloproteins. Experiments indicate that this chemistry is important in the context of oxidative damage and also may provide a first step in how DNA repair proteins may localize in the vicinity of lesions. This redox chemistry at a distance, mediated by the DNA helix, offers a route for long range signaling and coordination of DNA repair and DNA-processing proteins across the genome.

 Light refreshments will be served at 10:50 at The Coffee Lab, 510-643-0572