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Origin of bistability in the lac Operon
M Santillán1, M C Mackey, E S Zeron
1Unidad Monterrey, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Monterrey, México. moises.santillan@mac.com
Biophysical Journal
|March 14, 2007
Summary
Bistability in the lac operon ensures efficient glucose and lactose consumption by Escherichia coli. This emergent property guarantees induction only when glucose is scarce, optimizing nutrient utilization.
Area of Science:
- Systems Biology
- Molecular Biology
- Biophysics
Background:
- Multistability explains coexisting biological states.
- The lac operon exhibits bistability, crucial for gene regulation.
Purpose of the Study:
- Investigate the origin of lac operon bistability.
- Analyze the role of lactose metabolism in this bistability.
- Understand Escherichia coli's nutrient consumption efficiency.
Main Methods:
- Developed a mathematical model for the lac operon regulatory pathway.
- Compared model predictions with experimental data using a nonmetabolizable inducer.
- Performed stochastic numerical simulations.
Main Results:
- Lactose metabolism significantly alters the bistable region in external lactose (Le) and glucose (Ge) parameter space.
- Model predicts bistability can disappear for very low Ge.
- Bistability ensures the lac operon is induced only when glucose is nearly absent.
Conclusions:
- Bistability optimizes Escherichia coli's glucose and lactose consumption strategy.
- This emergent property preserves the stability of induced and uninduced states.
- Methods and findings are applicable to studying multistability in other biological systems.
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