Premium
On the Application of Polyelectrolyte “Limiting Laws” to the Helix‐Coil Transition of DNA. II. The Effect of Mg ++ Counterions
Author(s) -
Manning Gerald S.
Publication year - 1972
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.1972.360110503
Subject(s) - counterion , chemistry , polyelectrolyte , divalent , helix (gastropod) , limiting , salt (chemistry) , crystallography , nucleotide , thermodynamics , ion , organic chemistry , physics , polymer , biochemistry , mechanical engineering , ecology , snail , gene , engineering , biology
The techniques of the previous article are here applied to the case for which the solution contains, in addition to excess uni–univalent salt, one equivalent of divalent counterions per mole nucleotide. In agreement with the melting temperature measurements of Dove and Davidson for Mg ++ , it is predicted that a region of uni–univalent salt concentration then exists in which ( dT m / d log m A +) is negative. It is further predicted, in accord with experiment, that in the presence of divalent counterions, the helical form of DNA is much more stable than in their absence.