ION effects on the LAC repressor-operator interaction
نویسندگان
چکیده
منابع مشابه
Interpretation of monovalent and divalent cation effects on the lac repressor-operator interaction.
We have investigated the effects of mixed Na+: Mg2+ ionic solutions on the stability of the nonspecific lac repressor-DNA complex. The effects of Mg2+ are simply interpreted in terms of its role as a competitor (with repressor) for DNA sites. From these studies, the binding constant of the Mg-DNA complex can be determined as a function of the concentration of Na+. We have used this information ...
متن کاملModeling the Lac repressor-operator assembly: the influence of DNA looping on Lac repressor conformation.
Repression of transcription of the Escherichia coli Lac operon by the Lac repressor (LacR) is accompanied by the simultaneous binding of LacR to two operators and the formation of a DNA loop. A recently developed theory of sequence-dependent DNA elasticity enables one to relate the fine structure of the LacR-DNA complex to a wide range of heretofore-unconnected experimental observations. Here, ...
متن کاملThe mechanism and high-free-energy transition state of lac repressor–lac operator interaction
Significant, otherwise-unavailable information about mechanisms and transition states (TS) of protein folding and binding is obtained from solute effects on rate constants. Here we characterize TS for lac repressor(R)-lac operator(O) binding by analyzing effects of RO-stabilizing and RO-destabilizing solutes on association (ka) and dissociation (kd) rate constants. RO-destabilizing solutes (ure...
متن کاملStudies on gene control regions X. The effect of specific adenine-thymine transversions on the lac repressor-lac operator interaction.
Chemical and enzymatic methods were used to synthesize a transition (AT to GC) and a transversion (AT to TA) at a lac operator site known to interact with lac repressor through the thymine 5 methyl group. These operators also contained a poly(dA) . poly(dT) tail 8 to 12 base pairs in length at one end. Results suggest that the steric constraints of lac repressor relative to the position of the ...
متن کاملLac operator analogues: bromodeoxyuridine substitution in the lac operator affects the rate of dissociation of the lac repressor.
As measured by a decreased rate of dissociation, lac repressor binds 10-times tighter to 5-bromodeoxyuridine-substituted lac operator than it does to normal lac operator. This result is obtained both in the absence and in the presence of isopropylthiogalactoside, an inducing ligand. These data are significant with regard to the mechanism of sequence-specific protein-DNA interaction, and also su...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 1980
ISSN: 0006-3495
DOI: 10.1016/s0006-3495(80)84979-4