481d

[[Image:481d.jpg|left|200px]]<br /><applet load="481d" size="350" color="white" frame="true" align="right" spinBox="true"

caption="481d, resolution 1.60&Aring;" />

'''CRYSTAL STRUCTURE OF A HEXITOL NUCLEIC ACID (HNA) DUPLEX AT 1.6A RESOLUTION'''<br />

==Overview==

A huge variety of chemically modified oligonucleotide derivatives has been synthesized for possible antisense applications. One such derivative, hexitol nucleic acid (HNA), is a DNA analogue containing the standard nucleoside bases, but with a phosphorylated 1',5'-anhydrohexitol backbone. Hexitol nucleic acids are some of the strongest hybridizing antisense compounds presently known, but HNA duplexes are even more stable. We present here the first high-resolution structure of a double helical nucleic acid with all sugars being hexitols. Although designed to have a restricted conformational flexibility, the hexitol oligomer h(GTGTACAC) is able to crystallize in two different double helical conformations. Both structures display a high x-displacement, normal Watson-Crick base pairing, similar base stacking patterns, and a very deep major groove together with a minor groove with increased hydrophobicity. One of the conformations displays a major groove which is wide enough to accommodate a second HNA double helix resulting in the formation of a double helix of HNA double helices. Both structures show most similarities with the A-type helical structure, the anhydrohexitol chair conformation thereby acting as a good mimic for the furanose C3'-endo conformation observed in RNA. As compared to the quasi-linear structure of homo-DNA, the axial position of the base in HNA allows efficient base stacking and hence double helix formation.

 

==About this Structure==

481D is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=481D OCA].

 

==Reference==

Crystal structure of double helical hexitol nucleic acids., Declercq R, Van Aerschot A, Read RJ, Herdewijn P, Van Meervelt L, J Am Chem Soc. 2002 Feb 13;124(6):928-33. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11829600 11829600]

[[Category: Protein complex]]

[[Category: Declercq, R.]]

[[Category: Meervelt, L Van.]]

[[Category: dna analogue]]

[[Category: double helix]]

[[Category: hexitol nucleic acid]]