Sequence-Dependent Structural Variations of DNA Revealed by Chemical Ligation

Abstract
The comparative study of nick-sealing efficiency under the action of BrCN or water-soluble carbodiimide was carried out for 14 dinucleotide combinations in double helix. The difference between the lowest (17%, GpG) and the highest (94%, CpT) coupling yields was found to be more than five fold, both condensing reagents showing a similar sequence-specific trend. A strong correlation observed between coupling yields at different dinucleotide combinations and 31P NMR parameters supports the idea that variations in chemical ligation efficiency arise from sequence-specific modulations of the helix geometry and confirms close similarity of the intrinsic fine structure of intact and nicked DNAs.