Reactivity of B and Z-DNA towards N-acetoxy-2-acetylaminofluorene.

Poly d(G-C) d(G-C) in B-form, on one hand, and poly d(G-br5C). poly d(G-br5C) and poly d(G-m5C) . poly d(G-m5C) in Z-form, on another hand, were treated with N-AcO-[3H]AAF and the kinetics of these reactions were followed by radioactivity. Covalent binding of carcinogen to the polymers was evaluated after separation of the reacted polymers from non-reacted carcinogen by thin-layer chromatography. We found that B-form polymer reacts twice faster than the Z-form polymers. Proportions of main adducts in the three polymers are almost the same. Results are discussed in relation to the calculated electrostatic potential minima and steric accessibility at the reactive site (1, 2).