Speaker: De Witt Sumners, Robert O. Lawton Distinguished Prof. of Math, Co-Director
From: Program in Math and Molecular Biology (PMMB) Inst.of Molecular Biophysics, FSU
Date / Time / Room: Wednesday, April 21, 2004 / 4:00 PM / Hayes-Healy 127

Title: DNA Topology: Experiments and Analysis

Abstract: Cellular DNA is a long, thread-like molecule with remarkably complex topology. Enzymes which manipulate the geometry and topology of cellular DNA perform many important cellular processes (including segregation of daughter chromosomes, gene regulation, DNA repair, and generation of antibody diversity). 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 binding and mechanism can often be characterized. This expository lecture will discuss topological models for DNA strand passage and exchange, and using the spectrum of DNA knots to infer bacteriophage DNA packing in viral capsids.