ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
It has very recently been reported that deoxyribonucleic acid oligomers of cytosine with sequences such as d-T(CN)T aggregate into tetrastranded sructures [J. L. Leroy et al. (1993), Biochemistry, Vol. 32, pp. 6019-6031; K. Gehring et al. (1993), Nature, Vol. 363, pp. 561-565; S. Ahmed (1994), Structural Biology, Vol. 1, pp. 83-88]. Using gel filtration chromatography we have found that the oligomer dC10 aggregates into a mixture of duplex, tetraplex, and octaplex structures. We have also found that at the concentration used for Raman spectroscopy (0.05 M in base residues), these structures remain stable from pH 5 to pH 8 at 5°C. The Raman spectra of these oligomers in a 0.1 M NaCl solution at pH 7 and 5°C show a remarkable resemblance to the Raman spectra of the A-form double-helical ribonucleic acid polymer of cytosine taken at pH 5.5 and room temperature [C. H. Chen and G. J. Thomas, Jr. (1977), Biopolymers, Vol. 16, pp. 765-789]. This appears to be the first time that this A-type furanose ring pucker has been reported in deoxyoligonucleotides in aqueous solution at low salt and pH 5.5-7. The gel filtration chromatography and the uv melting behavior of the annealed dC10 solutions show the presence of an equilibrium mixture of multiplexes with multiple melting transitions. Very slow annealing of dC10 solutions in the pH range 6.5-7.0 also produced a similar equilibrium mixture of multiplexes, but at a much slower rate. Rapidly cooled samples tended to change to the equilibrium mixture over a period of several days. © 1997 John Wiley & Sons, Inc.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
Permalink
