ISSN:
1572-8927
Keywords:
poly(dG) · poly(dC)
;
poly(dG-dC) · poly(dG-dC)
;
polynucleotides
;
Raman spectra
;
thermotropism
;
structure
;
B to Z transition
;
Z to random coil transition
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Raman spectroscopic measurements on aqueous solutions of poly(dG) · poly(dC)indicate that the conformation of the polynucleotides in this double helicalcomplex are distributed between the A and B types at room temperature, the Aform being predominant at −15°C and decreasing progressively upon raising thetemperature to 65°C. A reversible pretransition has been found in this complexnear 70°C. Modifications in the spectra at this temperature indicate no majorconformational changes, but rather suggest altered base pairing and hydration ofthe carbonyl groups, accompanied by a slight distortion of the double helix,resulting in a slightly reduced stacking of the cytosine bases. Measurements inself-pressurized solutions of the complex at high temperature show that it meltsat 103°C in 0.1M NaCl solution (107°C in 0.5M NaCl). These values are somewhatlower than those we have determined in the same manner for the complexpoly(dG-dC) · poly(dG-dC): 117°C in 0.1M MgCl2 and 113°C or higher in 0.1MNaCl solution.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005147019985
