Hydration of single-stranded phosphodiester and phosphorothioate oligodeoxyribonucleotides.
AUTOR(ES)
White, A P
RESUMO
Infrared spectroscopy was used to identify hydration-sensitive structural differences between single- stranded phosphorothioate (PS) and phosphodiester (PO) oligodeoxyribonucleotides. Spectra were recorded in the mid-infrared region, 500-1800 cm-1, at relative humidities between 0 and 98%; the PS and PO spectra are substantially different. The hydration effects on spectral bands in these single-stranded oligodeoxyribonucleotides is markedly different from such behavior in double- and triple-stranded oligodeoxyribonucleotides. A strong absorption occurs at 656 cm-1 in the phosphorothioate sample which is completely absent from the PO spectra. Gravimetric measurements were carried out on one PS and one PO sample to monitor and confirm hydration. The calculated BET adsorption constants [Brunauer, S., Emmett, RH. and Teller, E. (1938) J. Am. Chem. Soc., 60, 309-319] are 1.2 and 1.4 water molecules per nucleotide in the first hydration layer of PS and PO respectively. While the gravimetric data indicate that the single-stranded oligodeoxyribonucleotides hydrate very similarly to duplex DNA, the mid-infrared conformational marker bands are strikingly different from those observed for duplex DNA. In particular, the Vas of the phosphate group (PO2) at 1222 cm-1 in the single-stranded PO spectra is independent of relative humidity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=146070Documentos Relacionados
- Interaction of the RecA protein of Escherichia coli with single-stranded oligodeoxyribonucleotides.
- Polyamine effects on purine-purine-pyrimidine triple helix formation by phosphodiester and phosphorothioate oligodeoxyribonucleotides.
- Different base per unit length ratios exist in single-stranded RNA and single-stranded DNA.
- Retrons and multicopy single-stranded DNA.
- Specific inhibition of the E.coli RecBCD enzyme by Chi sequences in single-stranded oligodeoxyribonucleotides