A Route to Cloning DNA Polyhedra
A pentagonal dodecahedron is illustrated with twelve exocyclic arms, in a representation know as a Schlegel diagram. This is a 2-D representation of a 3-D object in which the central polygon is closest to the reader, the polygons removed from the center are distorted and further behind in the page, and the outer polygon is at the rear of the figure. The Schlegel diagram of the dodecahedron is shown in red. Surrounding these red lines are double helices two turns long that have been drawn in cyan; these represent the double helical DNA corresponding to each edge of the dodecahedron. Each of the twelve pentagons contains an exocyclic double helical arm. In addition, each of the individual faces has been connected to a neighboring face via the exocyclic arms, so that the entire representation is a single long strand. The magenta lines represent the connecting DNA that links the pentagons to each other. The magenta curves are connected so as to make a formal knot, but the structure would need to be cleaved between these arrows in order to fold. Each exocyclic double helical segment would be designed to contain a restriction site, so that it can be severed from the connecting DNA. This DNA will be cut away upon formation of the structure. No attempt at topological representation is made here: All connecting DNA (magenta lines) lies behind the polygonal DNA for purposes of clarity.
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