Pseudo-dyad axis

Fig. 5. Three views of the NCP from Harp et al. [31]. (a) Ventral surface view, (b) Side view, (c) View down the molecular pseudo-dyad axis. The histones are represented by Ca ribbon models of the secondary structure elements, and the DNA model indicates the base pairing between complementary strands. The DNA is positioned asymmetrically by one-half base pair on the NCP. This results in a two sides arbitrarily referred to a dorsal and ventral (the surface shown here). The ventral surface of the NCP is best recognized by the extended N-terminal H3 tail protruding to the right. In these images, the pseudo-dyad axis is represented by vertical bars for both the ventral and side view. The pseudo-dyad axis passes through the center of the dyad view orthogonal to the plane of the page, (d) Color code for histone chains in the figures in this chapter. Note the change in hue denoting the two sides of the histone octamer.

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