Fig. 3.

Anisotropic bending reduces the configurational space available to a DNA chain. A preferred direction of bending—anisotropy—is conferred by particular sequence organisations and periodicity (and hence, more information) such as, for example, the alternating blocks of A/T and G/C rich sequences associated with DNA wrapping on the histone octamer. One consequence of reducing the degrees of configurational freedom is an increase in the summed vectorial stiffness of the duplex (the bicycle chain effect). In principle, the directionality of bending anisotropy can act either to promote or antagonize wrapping on a given protein surface