Right-handed and left-handed DNA: studies of B- and Z-DNA by using proton nuclear Overhauser effect and P NMR.

AUTOR(ES)

Patel, D J

RESUMO

We have differentiated between syn and anti glycosidic torsion angles in nucleic acid duplexes by measuring the transient nuclear Overhauser effect (NOE) between the sugar H-1' protons and the purine H-8 and pyrimidine H-6 base protons. The transient NOE measurements demonstrate a syn glycosidic torsion angle at guanosine and an anti glycosidic torsion angle at cytidine in poly(dG-dC) in 4 M NaCl and in poly(dG-m5dC) in 1.5 M NaCl solution. These features have been observed previously in the left-handed Z-DNA conformation of (dC-dG)3 in the crystalline state. By contrast, transient NOE studies demonstrate that both guanosine and cytidine residues adopt the anti conformation about the glycosidic bond for the right-handed poly(dG-dC) and poly(dG-m5dC) conformation in a low-salt solution. We have used P NMR to monitor the equilibrium between B- and Z-DNA forms of poly(dG-dC) in LiCl solutions; at high temperatures, the equilibrium shifts from B- to Z-DNA.

Documentos Relacionados

• Left-handed Z-DNA in bands of acid-fixed polytene chromosomes.
• Computation of ionic distributions around charged biomolecular structures: results for right-handed and left-handed DNA.
• Sequence dependence of base-pair stacking in right-handed DNA in solution: proton nuclear Overhauser effect NMR measurements.
• Antibodies specific for left-handed Z-DNA.
• Left-handed Z-DNA and in vivo supercoil density in the Escherichia coli chromosome.