Figure 5.

(A) Crystal structure of the NCP (Protein Data Bank Accession no. 1KX5) with 147 bp of DNA (nucleobases = purple, sugar-phosphate backbone = blue) modified to include a 10 bp extension and a covalently attached AQ (green) end-capped onto the DNA. The histone octamer is in orange. The relative positions of the guanine oxidation sites GG₁, G₁, and GG₂ of AQ-157TG are highlighted in yellow. (B) Illustration of the rotational position of the DNA major groove in the AQ-157TG rNCPs as deduced from Part A. The relative position of damage sites GG₁, G₁ and GG₂ with respect to the histone protein surface is indicated.