ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Laser-excited Raman spectra of the double-helical complexes poly A·poly U and poly G·poly C are reported for 2H2O and H2O solutions. The spectra are discussed in relation to their use as quantitative reference spectra for determining the dependence of the Raman scattering of RNA on secondary structure. The Raman line at 815 cm-1, due to the phosphodiester group, exhibits the same intrinsic intensity in spectra of poly A·poly U and poly G·poly C and is thus dependent only upon the amount of ordering of the helix and not on the kinds of nucleotides involved. The hypochromic Raman lines in spectra of poly A·poly U are identified and their intensity changes are determined quantitatively over the temperature range 32-85°C. Comparison of the spectra in the 1500-1750 cm-1 region reveals that the Raman lines from carbonyl group vibrations of uracil are about sevenfold more intense than those of guanine and cytosine for both paired and unpaired states and will thus dominate the spectra of RNA. The Raman frequencies in this region are also compared with previously reported infrared frequencies and give evidence of being strongly perturbed by base-stacking interactions in the helices.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1972.360111205
