Pentads, Hexads, Heptads, and Octads

The sequence length distribution for an ideal copolymerization with r = 5, r2 = 0.2 for an equimolar feed composition is shown in Fig. 6-9. This copolymerization has pn — p2 0.8333 andp 2— p22 — 0.1667. Both M and M propagating centers have a 5 1 tendency to add Mi over M2, but Mi pentad sequences are not the most plentiful, although they are among the most plentiful. The most plentiful sequence is Mi at 16.7% with 14.0%, 11.6%, 9.7%, 8.1%, 6.7%, 5.6%, and 4.7%, respectively, of dyad, triad, tetrad, pentad, hexad, heptad, and octad Mi sequences. There are smaller amounts of longer sequences 3.2% of... 

A nanosecond MD simulation of d(T4G4T4) from 1999 h clearly shown a destabilization of the syston when removing the metal ions fix>m the central ion chatmel. Interestingly, a very stable alternative conformation involving a guanine triad has been found in the simulations. This observation can be related to the fact that experimental DNA tetraplex structures may not only contain tetrads but also triads, pentads, hexads, heptads and octads. The two iimer G-tetrads of the four stacked tetrad planes exhibit contrary to the expoimental structure a bifurcated H-bond pattern. 

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