ISSN:
1432-1017
Keywords:
Key words Z-DNA
;
Kinetics
;
Circular dichroism
;
Salt-dependence
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract The salt-induced B- to Z-DNA conformational transition is a cooperative- and time-dependent process. From a modified form of the logistic equation which describes an equilibrium between two states we have deduced a kinetic function to quantify the degree of the B to Z transition of a synthetic (dG-dC) ⋅ (dG-dC) polynucleotide. This function was obtained by introduction of time as a variable in the logistic function so that the equilibrium constant, K, is replaced by a new constant K s , characteristic of the type of salt used. This constant is defined as the salt concentration needed to reach the B-Z transition-midpoint in the time unit. The equation fits the data obtained by circular dichroism (CD) for changes in molecular ellipticity of poly(dG-m5dC) ⋅ poly(dG-m5dC) and poly(dG-dC) ⋅ poly(dG-dC) incubated with various concentrations of mono-, di-, and trivalent salts at a constant temperature. The derived expression may be a very useful tool for studying the kinetics of the B- to Z-DNA transition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002490050150
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