ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Tm values of 16 fully complementary RNA duplexes with repeating base sequence have been employed as the empirical basis for developing a reliable and practical method for computing apparent enthalpies (ΔHcalc) for their helix → coil transitions. The approach taken is the same as in the accompanying investigation of DNA duplexes, although some of the computational variables of the “best-fit” function are necessarily different due to the distinguishing structural properties of the RNA-type helix. An excellent linear correlation was thus obtained between experimental Tm and ΔHcalc values. An equally good fit was obtained between Tm and ΔHcalc for five unrelated (to the 16 RNAs) decaribonucleotide duplexes. The differences in computational variables between the best-fit methods for RNA and DNA duplexes are shown to be a reflection of differences in cation binding and the effective local dielectric. The greater Tm dependence on G·C content of RNA helices than of DNA helices is shown to be due to a greater latitude of stacking stabilities of complementary dinucleotide fragments containing A·T than A·U base pairs.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360220812
