In this paper, the novel topology of DNA knots is discussed on the basis of the Seifert construction in knot theory. Our result shows that T4k-DNA knots possess the point symmetry group S1 and T2k+1-DNA knots possess the point symmetry group C1-Hence, C, represents the most chiral and S1 the least achiral We say that a structure with C1 symmetry is topologically chiral, wile a structure with S1 Symmetry is shown to have the properties of a topological rubber glove, and that the orientability of the Seifert construction is primary tool for the left-right classification of molecular knots.

DNA polyhedra are cage-like architectures based on interlocked and interlinked DNA strands. We propose a formula which unites the basic features of these entangled structures. It is based on the transformation of the DNA polyhedral links into Seifert surfaces, which removes all knots. The numbers of components m, of crossings c, and of Seifert circles s are related by a simple and elegant formula: szm~cz2. This formula connects the topological aspects of the DNA cage to the Euler characteristic of the underlying polyhedron. It implies that Seifert circles can be used as effective topological indices to describe polyhedral links. Our study demonstrates that, the new Euler’s formula provides a theoretical framework for the stereo-chemistry of DNA polyhedra, which can characterize enzymatic transformations of DNA and be used to characterize and design novel cages with higher genus.

A new methodology for understanding the construction of polyhedral links has been developed on the basis of the Platonic and Archimedean solids by using our method of the ‘three-cross-curve and double-twist-line covering’. There are five classes of polyhedral links that can be explored: the tetrahedral and truncated tetrahedral links; the hexahedral and truncated hexahedral links; the dodecahedral and truncated dodecahedral links; the truncated octahedral and icosahedral links. Our results show that the tetrahedral and truncated tetrahedral links have T symmetry; the hexahedral and truncated hexahedral links, as well as the truncated octahedral links, O symmetry; the dodecahedral and truncated dodecahedral links, as well as the truncated icosahedral links, I symmetry, respectively. This study provides further insight into the molecular design, as well as theoretical characterization, of the DNA and protein catenanes.

This paper extends the methodology of the construction of polyhedral links by tangles in knot theory. Building blocks consist of odd tangles which are regions in the projection plane with 2n+1 half-twist, where n is an integer. Fixing odd tangles at the all vertices of Extend Goldberg polyhedra, and then connect them together will result in many interlocked networks. The solution to the component algorithm of 4-regular polyhedral links has been proposed. Our result shows, by counting the length of central circuits of a polyhedron, the component number of the relating polyhedral link will be presented. Using such topological models, some potential significance in biological and chemical areas is tested to be explored.