Figure 3.

Tetrahedrons with two or three stem-loops at their vertices can be assembled to form kissing complexes. (A and B) Schematic drawings of the tetrahedrons. Whereas the stem sequence is the same for all stem-loop elements, two complementary loop sequences (1 and 2) exist, as represented by differently colored circles (dark and light arrows) (Supplementary Figure S1). (C) Different DNA tetrahedrons, as schematically shown at the top of the lanes, were hybridized in the presence of 11.5 mM Mg2+ (representative result of at least three independent repetitions). Dimeric tetrahedron complexes are indicated by black triangles. Separation of monomeric tetrahedrons and kissing complexes was performed with a 4% polyacrylamide gel and was visualized by fluorescence staining.