CCMS Colloquium: Molecular Pasta, Complex Entanglement in Biopolymers (Dorothy Buck, Duke Uni.)

Speaker: Dorothy Buck, Professor of Mathematics, Duke University

Title: Molecular Pasta: Complex Entanglement in Biopolymers

Abstract: If you’ve cooked spaghetti, you’ve probably noticed how the pasta becomes entangled in the pot (especially in a small volume of water) or in your bowl afterwards.  This is a macro example of what I like to think about: entanglement in biopolymers.  Like linguine in a boiling pot of water, our own DNA is a (group of) long skinny molecule(s) in the confined volume of an active, energetic cell.  Unlike fettuccine though, it’s life-or-death important to organize, access and groom these long skinny DNA molecules.  So there’s a host of small machines (proteins) to do this, in ways we’ve yet to fully understand.  Part of the complication is that we don’t yet have the precise experimental tools yet to watch (through microscopes) this dynamic process.  So instead we use the shape of these DNA molecules — before, during and after their grooming — to back solve the precise processes that must be happening within the cell.

In this talk, I’ll give an overview of some of these molecular biological questions, why we care about them (as humans, biologists and mathematicians) and some of my answers to these.  In particular I’ll highlight some more recent work on understanding DNA spatial graphs, including those that look the the Greek letter theta, and the exciting new mathematics we’ve developed to accurately model DNA during cell division

Bio: Dorothy Buck is an alumna of Pomona College, and credits the Pomona Math department — including Professors Shahriar Shahriari, Richard Elderkin and especially Erica Flapan — for igniting a love of both math and academia. Her 20+ years of research has worked to characterize entanglement – in circles, linear segments and graphs – and to explore how biomolecular entanglement affects cellular structure and function. She investigates this molecular entanglement using a combination of topological (3-manifold) techniques and occasionally biochemical experiments.

She’s currently a professor at Duke, after faculty positions in the US (Brown and Johns Hopkins) and the UK, and much earlier an NSF postdoc and PhD with advisors in both Math and Molecular Biology.  After many years at the bench, she now collaborates with experimental and computational experts.  She’s been the recipient of over $5M in grants, which has funded both her own research and her large team, as well as projects with architects and an Artist in Residence.