Monday,
Februare 14, 2005, 11:00 a.m. SS 314
Topological Analysis of Enzymatic Actions:
Site-Specific
Recombinases and Topoisomerases
Abstract
DNA topology is the study of geometrical
(supercoiling)
and topological (knotting) properties of DNA loops and circular
DNA molecules. Virtually every reaction involving DNA is
influenced
by DNA topology, or has topological effects. Site-specific
recombinases and topoisomerases are enzymes able to change the
topology of circular DNA by breaking the DNA and introducing one
or more crossing changes. Mathematical analysis of such changes
may provide relevant information about the possible enzymatic
pathways, and about DNA conformation at the moment of
double-stranded break induction. In this talk I will discuss
some
of the problems that I am currently interested in, and the
topological tools used in their analyses.
First I will talk about Xer recombination and how we applied,
and extended, the tangle model for site-specific recombination
to
propose a unique topological mechanism for this enzymatic
action.
I will then present the Java applet TangleSolve that makes the
tangle model easily accessible to the scientific community.
Finally, I will talk about my recent work on DNA unknotting by
type II topoisomerase.
For further information please contact:
mittelmann@asu.edu