Wednesday, October 25/10:30 AM
IP6
The Topology of DNA
Cellular DNA is a long, thread-like molecule with remarkably complex topology. Many important cellular processes (including segregation of daughter chromosomes, gene regulation, DNA repair, and generation of antibody diversity) are mediated by enzymes that manipulate the geometry and topology of cellular DNA. Some enzymes pass DNA through itself via enzyme-bridged transient breaks in the DNA; other enzymes break the DNA apart and reconnect it to different ends. In the topological approach to enzymology, circular DNA is incubated with an enzyme, producing an enzyme signature in the form of DNA knots and links. By observing the changes in DNA geometry (supercoiling) and topology (knotting and linking) due to enzyme action, the enzyme mechanism can often be characterized. The speaker will discuss topological models for the structure of DNA and the active enzyme-DNA complex.
De Witt Sumners
Department of Mathematics
Florida State University
7/21/95