CD of the synthetic RNA duplexes poly[r(A-T)] and poly[r(A-U)] in salt and ethanolic solutions
Language English Country United States Media print
Document type Comparative Study, Journal Article, Research Support, Non-U.S. Gov't
PubMed
1691930
DOI
10.1002/bip.360290210
Knihovny.cz E-resources
- MeSH
- Time Factors MeSH
- Ammonium Chloride MeSH
- Circular Dichroism MeSH
- Ethanol MeSH
- Nucleic Acid Conformation MeSH
- Oligoribonucleotides MeSH
- Osmolar Concentration MeSH
- Poly A-U MeSH
- Poly A MeSH
- Poly T MeSH
- RNA * MeSH
- Solutions MeSH
- Base Composition MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
- Names of Substances
- Ammonium Chloride MeSH
- Ethanol MeSH
- Oligoribonucleotides MeSH
- poly A-T MeSH Browser
- Poly A-U MeSH
- Poly A MeSH
- Poly T MeSH
- RNA * MeSH
- Solutions MeSH
Synthetic RNA poly[r(A-T)] has been synthesized and its CD spectral properties compared to those of poly[r(A-U)], poly[d(A-T)], and poly[d(A-U)] in various salt and ethanolic solutions. The CD spectra of poly[r(A-T)] in an aqueous buffer and of poly[d(A-T)] in 70.8% v/v ethanol are very similar, suggesting that they both adopt the same A conformation. On the other hand, the CD spectra of poly[r(A-T)] and of poly[r(A-U)] differ in aqueous, and even more so in ethanolic, solutions. We have recently observed a two-state salt-induced isomerization of poly[r(A-U)] into chiral condensates, perhaps of Z-RNA [M. Vorlícková, J. Kypr, and T. M. Jovin, (1988) Biopolymers 27, 351-354]. It is shown here that poly[r(A-T)] does not undergo this isomerization. Both the changes in secondary structure and tendency to aggregation are different for poly[r(A-T)] and poly[r(A-U)] in aqueous salt solutions. In most cases, the CD spectrum of poly[r(A-U)] shows little modification of its CD spectrum unless the polymer denatures or aggregates, whereas poly[r(A-T)] displays noncooperative alterations in its CD spectrum and a reduced tendency to aggregation. At high NaCl concentrations, poly[r(A-T)] and poly[r(A-U)] condense into psi(-) and psi(+) structures, respectively, indicating that the type of aggregation is dictated by the polynucleotide chemical structure and the corresponding differences in conformational properties.
References provided by Crossref.org
Comparison of the solution and crystal conformations of (G + C)-rich fragments of DNA
Conformational transitions of poly(dA-bromo5dU) and poly(dA-iodo5dU) in solution