31P-NMR analysis of the B to Z transition in double-stranded (dC-dG)3 and (dC-dG)4 in high salt solution.

AUTOR(ES)

Holak, T A

RESUMO

In 4M NaCl solutions (dC-dG)n (n = 3,4; approximately 9 mM) exist as a mixture o +/- B and Z forms. The low and high field components of two 31P NMR resonances originating from internal phosphodiester groups are assigned to the GpC and CpG linkages, respectively. Low temperatures stabilize the Z-forms, which completely disappear above 50 degrees C (n = 3) and 65 degrees C (n = 4). delta H = -44 and -17 kJ/mol for B to Z transition in the hexamer and octamer duplexes, respectively. Temperature dependent changes (0-50 degrees C range) in the spin-lattice relaxation times at 145.7 MHz are distinctly different for the 31P nuclei o +/- GpC and CpG groups. The relaxation data can be explained by assuming that the GpC phosphodiester groups undergo more local internal motion than do the CpG groups.

Documentos Relacionados

• A one- and two-dimensional NMR study of the B to Z transition of (m5dC-dG)3 in methanolic solution.
• The 31P-NMR spectrum of the dodecamer d(GACGATATCGTC).
• Novel strategy for synthesis of full-length double-stranded cDNA transcripts without dC-dG tails.
• 31P-NMR Spectroscopy of Roots of Intact Corn Seedlings 1
• "Alternating B-DNA" conformation for the oligo(dG-dC) duplex in high-salt solution.