Colloquium: Knotting in proteins and other open curves

Eric Rawdon, University of St. Thomas
Manchester 016

Abstract: Some proteins (in their folded form) are classified as being knotted. The function of the knotting is mysterious since knotting seemingly would make the folding process unnecessarily complicated.  To function, proteins need to fold quickly and reproducibly, and misfolding can have catastrophic results.  For example, Mad Cow disease and the human analog, Creutzfeldt-Jakob disease, come from misfolded proteins.

Traditionally, knotting is only defined for closed curves, where the topology is trapped in the loop.  However, proteins have free ends, as well as most of the objects that humans consider as being knotted (like shoelaces and strings of lights).  Defining knotting in open curves is tricky and ambiguous.  We consider some definitions of knotting in open curves and see how one of these definitions is used to characterize the knotting in proteins.