Comparison of X-ray crystal structures of a tetradecamer sequence d(CCCGGGTACCCGGG)2 at 1.7 Å resolution.

We presented a comparison of three different X-ray crystal structures of DNA tetradecamer sequence d(CCCGGGTACCCGGG)2 all at about 1.7 Å resolution. The sequence was designed as an attempt to form a DNA four-way junction with A-type helical arms. Crystals did not have any metal ion in the crystallization solution apart from the sodium in the buffer. However, the sequence does not take up the junction structure, but forms an A-type double helix in P41212 space group.