Interaction between the left‐handed Z‐DNA and polyamine The crystal structure of the d(CG)3 and N‐(2‐aminoethyl)‐1,4‐diamino‐butane complex

Abstract
The DNA fragment d(CG)3 was co‐crystallized with N‐(2‐aminoethyl)‐1,4‐diaminobutane (PA(24)), a chemically synthesized polyamine. The complex crystal contained one polyamine, 3 magnesium cations and one sodium cation per duplex of d(CG)3, and well diffracted the X‐ray intensities up to 1.0 Å resolution. The d(CG)3 took a left‐handed Z‐DNA conformation, and the PA(24) molecule electrostatically interacted with the phosphate groups of the d(CG)3 duplex.