Premium
The influence of single‐strand breaks on the kinetics of denaturation of DNA
Author(s) -
Hoff A. J.,
Blok Joh.
Publication year - 1970
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.1970.360091105
Subject(s) - chemistry , temperature jump , kinetics , denaturation (fissile materials) , relaxation (psychology) , dna , ionic strength , biophysics , crystallography , ionic bonding , chemical physics , thermodynamics , ion , biochemistry , aqueous solution , organic chemistry , physics , nuclear chemistry , psychology , social psychology , quantum mechanics , biology
The influence of single‐strand breaks on the kinetics of the relaxation of DNA in a solution of low ionic strength has been investigated by a temperature jump method. The relaxation of DNA after a jump of 0.7 °C in the melting region has been monitored by measuring the extinction at 260 nm. For essentially monodisperse T4 DNA ( M = 130 × 10 6 ) two distinct relaxation times have been observed, that depend markedly on the initial extent of denaturation 1 − θ. The larger relaxation time decreases from 450 sec to about 300 sec, the smaller one from 55 see to 30 when 1 − θ increases from 0.03 to about 0.8. The dependence of these relaxation times on the average number of single‐strand breaks per molecule ( p ) appears to be very small up to p = 100. However, the relative contribution of the slow process decreases sharply when p increases from 0.6 to 30 and remains nearly constant for larger p . The observations are discussed in the light recent theories of the kinetics of denaturation.