ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In order to analyze the melting behavior of 5′-rGMP gel at acidic pH and self-aggregate near neutral pH we have obtained Raman spectra of aqueous solutions of 5′-rGMP at various temperatures. At low temperature the intensities of Raman peaks at 502, 585, 1083, 1179, 1322, 1366, 1487, and 1578 cm-1 decrease due to the formation of ordered structure (Raman hypochromism). In contrast, the peaks at 671, 725, 813, and 1338 cm-1 become stronger at low temperature (Raman hyperchromism). The Raman hyperchromism of the 671- and 813-cm-1 peaks have been explained in terms of detailed structural models. Recently, the 668- and 682-cm-1 peaks in the Raman spectrum of aqueous 5′-rGMP solution have been attributed to the guanine ring breathing vibrations in C3′- and C2′-endo conformers [Benevides, J. B., Lemur, D. & Thomas, G. J., Jr. (1984) Biopolymers 23, 1011-1024]. On the basis of this information our Raman data can be interpreted to suggest that the continuous helix model of 5′-rGMP gel is right-handed. The 1487-cm-1 peak intensity has been used to monitor the melting profies at several pHs. Near neutral pH the melting profile shows a single transition, whereas at acidic pH it shows two transitions. From these observations we propose possible pathways for the melting of 5′-rGMP gel formed at acidic pH and self-aggregate formed near neutral pH.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360250415
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