Information Technology Reference
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Fig. 2.7
Parallel arrangement of acute (top) or obtuse (bottom) monomeric triangles are im-
possible
Figures 2.9 and 2.10 are different looks of the same structure, where paired
monomeric triangles form a rotation angle around the pairing line. This implies
that they can be located inside a cylinder shape that is completely characterized by
a radius and by three angles: the rotation angle
ρ
, between two concatenated trian-
gles, the rotation angle
between
the concatenation segment of the triangle with the cylinder axis. From an evaluation
of these values, and of cylinder radius, the average length of edges of monomeric
triangles can be estimated (fractions of a nanometer) [44].
When many modules of the kind given in Fig. 2.10 are arranged, we obtain the
bilinear structure with a spiral shape, which grows internally to a cylinder, as shown
in Fig. 2.11, that is, the DNA double helix structure appears in its pure geometrical
form.
In Figure 2.12, we can see the empty internal cylinder formed by the paired
monomeric triangles along the DNA helix.
Φ
between two paired triangles, and the angle
τ
