Effects of knot tightness at the molecular level

Significance Knots and entanglements occur in proteins, DNA, and synthetic polymers and are being used to form the basis of interwoven nanomaterials. Understanding how the tautness of molecular entanglements affects properties is crucial for the future design of knotted, woven, and entangled molecules and materials. However, while there are many theoretical studies on such systems there are very few experimental studies. Here we investigate the influence of knot tightness in a range of physical and chemical properties for three knots tied in 20-, 23-, and 26-nm closed-loop strands. We find that the tightness of the molecular knots significantly affects reactivity, conformation, and the expression of chirality.