Topological Complexity in Protein Structures

For DNA molecules, topological complexity occurs exclusively as the result of knotting or linking of the polynucleotide backbone. By contrast, while knots and links have been found within the polypeptide backbones of protein structures, non-planarity can also result from the entanglement between a polypeptide chain and inter- and intra-chain linking via cofactors, metal ions, and disulfide bonds. In this talk, we describe knots, links, and non-planar graphs that have been identified in protein structures and present mathematical models explaining how protein knots might occur.