Crystallization and preliminary X-ray analysis of the DNA decamers d(CCGGATCCGG) and d(CCGGCGCCGG)

Abstract

The DNA decamers d(CCGGATCCGG) and d(CCGGCGCCGG) have been crystallized for X-ray analysis in order to investigate the effects of changing the two central base pairs of the DNA fragment d(CCGGGACCGG). Previous studies have already demonstrated that the structure of the former DNA fragment contains a DNA Holliday junction. Crystals were obtained at 293 K by the hanging-drop vapour-diffusion technique using the Nucleic Acid Mini Screen. Over a period of two weeks, hexagonal plates appeared. For the DNA fragment d(CCGGATCCGG), the crystals belong to space group P3(1), with unit-cell parameters a = b = 33.54, c = 46.39 A, alpha = beta = 90, gamma = 120 degrees, and diffract to 2.2 A. In the case of the DNA fragment d(CCGGCGCCGG) the crystals belong to the space group C2, with unit-cell parameters a = 65.35, b = 24.07, c = 37.34 A, beta = 109.97 degrees, and diffract to 2.0 A.