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On the hydration of DNA. II. Base composition dependence of the net hydration of DNA
Author(s) -
Tunis MaryJane B.,
Hearst John E.
Publication year - 1968
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1968.360060909
Subject(s) - chemistry , thymine , cytosine , composition (language) , dna , guanine , nucleobase , mole , base (topology) , nucleotide , organic chemistry , biochemistry , mathematical analysis , linguistics , philosophy , mathematics , gene
The dependence of the net hydration of DNA on its base composition has been measured by density gradient ultracentrifugation of three DNA's in a series of cesium and lithium salt solutions of different water activities. Extrapolation to zero water activity showed the dependence of the partial specific volume on base composition to be very small for CsDNA and aero for LiDNA. At least 99% of the dependence of buoyant density on base composition can be accounted for on the basis of a differential hydration, with a mole of adenine–thymine pairs binding about 2 moles more water than a mole of guanine–cytosine pairs in CsCl.