Induction of the lac promoter in the absence of DNA loops and the stoichiometry of induction
| Autor: | Stefan Oehler, Siegfried Alberti, Benno Müller-Hill |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
DNA
Bacterial Transcriptional Activation Operator (biology) Operator Regions Genetic lac operon Lac repressor Biology Article trp operon chemistry.chemical_compound In vivo Genetics Escherichia coli Inducer Promoter Regions Genetic Models Genetic Gene Expression Regulation Bacterial Repressor Proteins Biochemistry chemistry Lac Operon Biophysics bacteria Nucleic Acid Conformation L-arabinose operon DNA |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 0305-1048 |
| Popis: | In vivo induction of the Escherichia coli lactose operon as a function of inducer concentration generates a sigmoidal curve, indicating a non-linear response. Suggested explanations for this dependence include a 2:1 inducer-repressor stoichiometry of induction, which is the currently accepted view. It is, however, known for decades that, in vitro, operator binding as a function of inducer concentration is not sigmoidal. This discrepancy between in vivo and in vitro data has so far not been resolved. We demonstrate that the in vivo non-linearity of induction is due to cooperative repression of the wild-type lac operon through DNA loop formation. In the absence of DNA loops, in vivo induction curves are hyperbolic. In the light of this result, we re-address the question of functional molecular inducer-repressor stoichiometry in induction of the lac operon. |
| Databáze: | OpenAIRE |
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