A. Lee et Tv. Chalikian, Volumetric characterization of the hydration properties of heterocyclic bases and nucleosides, BIOPHYS CH, 92(3), 2001, pp. 209-227
We have determined the partial molar volumes, expansibilities and adiabatic
compressibilities of six heterocyclic nucleic acid bases, five ribonucleos
ides and six 2'-deoxyribonucleosides within the temperature range 18-55 deg
reesC. We interpret the resulting data in terms of the hydration of the com
ponent hydrophobic and polar atomic groups. From our temperature-dependent
volumetric studies, we found that the total contraction of water caused by
polar groups of each individual heterocyclic base and nucleoside depends on
the proximity and chemical nature of other functional groups of the solute
. In addition, the compressibility contributions of polar groups vary great
ly in sign and magnitude depending on the surrounding functional groups. In
agreement with previous studies, our results are suggestive of little or n
o interaction between the sugar and base moieties of a nucleoside. In gener
al, our data shed light into the hydration properties of individual heteroc
yclic bases and nucleosides, which may have significant implications for th
e sequence-dependent hydration of nucleic acids. We discuss the potential i
mportance of our results for developing an understanding of the role that s
olvent plays in the stabilization/destabilization of nucleic acid structure
s. (C) 2001 Elsevier Science B.V. All rights reserved.