1s23

Publication Abstract from PubMed

The deoxyoligonucleotide d(CGCAATTGCG) has previously been crystallized in four different space groups. The crystals diffract to moderate resolution (2.3-2.9 A). Here, a fifth crystal form that diffracts to higher resolution (1.6 A) is presented which was obtained thanks to the use of Co2+ and cryogenic temperatures. The availability of five different crystal structures allows a thorough analysis of the conformational variability of this DNA sequence. It is concluded that the central hexamer sequence CAATTG has a practically constant conformation under all conditions, whilst the terminal base pairs at both ends vary considerably as a result of differing interactions in the crystals. The new crystal structure presented here is stabilized by guanine-Co2+-guanine interactions and the formation of C1+ -G8.C3 triplexes between neighbouring duplexes. As a result of the higher resolution of the crystal structure, a more regular structure was obtained and a clear definition of the spine of hydration was observed which was not visible in the four previous structures.

DNA variability in five crystal structures of d(CGCAATTGCG).,Valls N, Wright G, Steiner RA, Murshudov GN, Subirana JA Acta Crystallogr D Biol Crystallogr. 2004 Apr;60(Pt 4):680-5. Epub 2004, Mar 23. PMID:15039556^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.