Abstract
Salt induced transitions between four conformations of the methylated ribo-deoxyribo co-polymer poly (rG-m5dC).poly (rG-m5dC) have been studied using phosphorous-NMR, Raman spectroscopy, and circular dichroism. A high salt A-Z transition is observed for the polymer. However, the methylated polymer does not enter the high salt Z form more readily than the analogous unmethylated polymer, unlike the effect of methylation on the fully deoxy polymer poly (dG-dC).poly (dG-dC). The methylated polymer fails to undergo a low salt A-Z transition in 5 mM Tris buffer, unlike the unmethylated poly (rG-dC).poly (rG-dC). However, if the counterion is changed to triethanolamine buffer, an A-Z transition does take place. In 5 mM Tris buffer the phosphorous-NMR spectrum of poly (rG-m5dC).poly (rG-m5dC) shows one resonance in the absence of NaCl that splits into two closely spaced resonances as the NaCl level is increased to 30 mM. The Raman spectrum of poly (rG-m5dC).poly (rG-m5dC) shows that it is in the A conformation at intermediate salt concentrations. From this we conclude that poly (rG-m5dC).poly (rG-m5dC) is in a regular A conformation in Tris buffer at low Na+ levels, shifting to an alternating A conformation with a dinucleotide repeat at intermediate salt concentrations.
Full text
PDF









Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Behe M., Felsenfeld G. Effects of methylation on a synthetic polynucleotide: the B--Z transition in poly(dG-m5dC).poly(dG-m5dC). Proc Natl Acad Sci U S A. 1981 Mar;78(3):1619–1623. doi: 10.1073/pnas.78.3.1619. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chen C. W., Cohen J. S. Salt- and sequence-dependence of the secondary structure of DNA in solution by 31P-NMR spectroscopy. Biopolymers. 1983 Mar;22(3):879–893. doi: 10.1002/bip.360220310. [DOI] [PubMed] [Google Scholar]
- Chen C., Cohen J. S., Behe M. B to Z transition of double-stranded poly[deoxyguanylyl(3'-5')-5-methyldeoxycytidine] in solution by phosphorus-31 and carbon-13 nuclear magnetic resonance spectroscopy. Biochemistry. 1983 Apr 26;22(9):2136–2142. doi: 10.1021/bi00278a013. [DOI] [PubMed] [Google Scholar]
- Hall K., Cruz P., Tinoco I., Jr, Jovin T. M., van de Sande J. H. 'Z-RNA'--a left-handed RNA double helix. Nature. 1984 Oct 11;311(5986):584–586. doi: 10.1038/311584a0. [DOI] [PubMed] [Google Scholar]
- Hartmann B., Pilet J., Ptak M., Ramstein J., Malfoy B., Leng M. The B reversible Z transition of poly(dI-br5dC).poly(dI-br5dC). A quantitative description of the Z form dynamic structure. Nucleic Acids Res. 1982 May 25;10(10):3261–3277. doi: 10.1093/nar/10.10.3261. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Joyce C. M., Grindley N. D. Construction of a plasmid that overproduces the large proteolytic fragment (Klenow fragment) of DNA polymerase I of Escherichia coli. Proc Natl Acad Sci U S A. 1983 Apr;80(7):1830–1834. doi: 10.1073/pnas.80.7.1830. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Klug A., Jack A., Viswamitra M. A., Kennard O., Shakked Z., Steitz T. A. A hypothesis on a specific sequence-dependent conformation of DNA and its relation to the binding of the lac-repressor protein. J Mol Biol. 1979 Jul 15;131(4):669–680. doi: 10.1016/0022-2836(79)90196-7. [DOI] [PubMed] [Google Scholar]
- Malfoy B., Rousseau N., Leng M. Interaction between antibodies to Z-form deoxyribonucleic acid and double-stranded polynucleotides. Biochemistry. 1982 Oct 26;21(22):5463–5467. doi: 10.1021/bi00265a013. [DOI] [PubMed] [Google Scholar]
- Nishimura Y., Tsuboi M., Nakano T., Higuchi S., Sato T., Shida T., Uesugi S., Ohtsuka E., Ikehara M. Raman diagnosis of nucleic acid structure: sugar-puckering and glycosidic conformation in the guanosine moiety. Nucleic Acids Res. 1983 Mar 11;11(5):1579–1588. doi: 10.1093/nar/11.5.1579. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Patel D. J., Canuel L. L., Pohl F. M. "Alternating B-DNA" conformation for the oligo(dG-dC) duplex in high-salt solution. Proc Natl Acad Sci U S A. 1979 Jun;76(6):2508–2511. doi: 10.1073/pnas.76.6.2508. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Patel D. J., Kozlowski S. A., Nordheim A., Rich A. Right-handed and left-handed DNA: studies of B- and Z-DNA by using proton nuclear Overhauser effect and P NMR. Proc Natl Acad Sci U S A. 1982 Mar;79(5):1413–1417. doi: 10.1073/pnas.79.5.1413. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Patel D. J., Kozlowski S. A., Suggs J. W., Cox S. D. Right-handed alternating DNA conformation: poly(dA-dT) adopts the same dinucleotide repeat with cesium, tetraalkylammonium, and 3 alpha, 5 beta, 17 beta-dipyrrolidinium steroid dimethiodide cations in aqueous solution. Proc Natl Acad Sci U S A. 1981 Jul;78(7):4063–4067. doi: 10.1073/pnas.78.7.4063. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pohl F. M., Jovin T. M. Salt-induced co-operative conformational change of a synthetic DNA: equilibrium and kinetic studies with poly (dG-dC). J Mol Biol. 1972 Jun 28;67(3):375–396. doi: 10.1016/0022-2836(72)90457-3. [DOI] [PubMed] [Google Scholar]
- Shindo H., Simpson R. T., Cohen J. S. An alternating conformation characterizes the phosphodiester backbone of poly(dA-dT) in solution. J Biol Chem. 1979 Sep 10;254(17):8125–8128. [PubMed] [Google Scholar]
- Uesugi S., Ohkubo M., Ohtsuka E., Ikehara M., Kobayashi Y., Kyogoku Y., Westerink H. P., van der Marel G. A., van Boom J. H., Haasnoot C. A. Conformation of ribooligonucleotide duplexes containing an alternating C-G sequence which show an unusual circular dichroism spectrum. J Biol Chem. 1984 Feb 10;259(3):1390–1393. [PubMed] [Google Scholar]
- Wu H. Y., Behe M. J. Salt-induced Z-A-Z transition sequence in the mixed ribo-deoxyribo copolymer poly(rG-dC) X poly(rG-dC). Proc Natl Acad Sci U S A. 1984 Dec;81(23):7284–7287. doi: 10.1073/pnas.81.23.7284. [DOI] [PMC free article] [PubMed] [Google Scholar]
