214d
From Proteopedia
THE SOLUTION STRUCTURE OF A DNA DUPLEX CONTAINING A SINGLE 2'-O-METHYL-BETA-D-ARAT
Overview
Two-dimensional 1H NMR spectroscopy was used to determine the solution structure of the double-stranded DNA oligonucleotide d(5'-CGCATATAGCC-3'): d(5'-GGCTAXATGCG-3'), where X is 1-(2-O-methyl-beta-D-arabinofuranosyl)thymine. The structure determination was based on a total relaxation matrix analysis of NOESY cross-peak intensities using the MARDIGRAS program. The improved RANDMARDI procedure was used during the calculations to include the experimental "noise" in the NOESY spectra. The NOE-derived distance restraints were applied in restrained molecular dynamics calculations. Twenty final structures each were generated for the modified DNA duplex from both A-form and B-form DNA starting structures. The root-mean-square deviation of the coordinates for the 40 structures was 0.82 A. The duplex adopts a normal B-DNA-type helix, and the spectra as well as the structure show that the modified nucleotide X adopts a C2'-endo (S) sugar conformation. There are no significant changes in the helix originating from the modified nucleotide. The CH3O group on X is directed toward the major groove, and there seems to be free space for further modifications at this position.
About this Structure
Full crystallographic information is available from OCA.
Reference
Structure of a DNA duplex containing a single 2'-O-methyl-beta-D-araT: combined use of NMR, restrained molecular dynamics, and full relaxation matrix refinement., Gotfredsen CH, Spielmann HP, Wengel J, Jacobsen JP, Bioconjug Chem. 1996 Nov-Dec;7(6):680-8. PMID:8950487 Page seeded by OCA on Sat May 3 18:18:53 2008
