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Characterization of Membrane Transporters by Heterologous Expression in E. coli and Production of Membrane Vesicles
Published on: December 31, 2019
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Binding proteins enhance specific uptake rate by increasing the substrate-transporter encounter rate
Evert Bosdriesz1, Stefanía Magnúsdóttir1, Frank J Bruggeman1
1Systems Bioinformatics, VU University, Amsterdam, The Netherlands.
The FEBS Journal
|April 8, 2015
Summary
Binding proteins enhance nutrient scavenging in microorganisms by increasing transporter efficiency. Higher binding protein concentrations optimize nutrient uptake, especially when nutrients are scarce.
Area of Science:
- Microbiology
- Biochemistry
- Systems Biology
Background:
- Microorganisms utilize binding-protein assisted active transport for nutrient acquisition.
- Existing research proposes advantages of binding proteins but lacks quantitative analysis.
- A systematic investigation into the precise function of binding proteins is needed.
Purpose of the Study:
- To quantitatively analyze the function of binding proteins in nutrient transport systems.
- To derive kinetic, thermodynamic, and stoichiometric properties of these systems.
- To test the hypothesis that maximal specific activity is the selection objective.
Main Methods:
- Combining knowledge of selection pressure and physicochemical constraints.
- Deriving theoretical properties of binding-protein dependent transport.
- Analyzing the impact of binding protein concentration on transport efficiency.
Main Results:
- Binding protein concentration should exceed both nutrient and transporter concentrations for maximal activity.
- Elevated binding protein levels increase the encounter rate between transporters and loaded binding proteins.
- This mechanism enhances affinity and specific uptake rates, particularly at low substrate concentrations.
Conclusions:
- Binding-protein dependent transport systems are optimized for maximal import activity per transporter.
- The concentration of binding proteins is a critical factor in efficient nutrient scavenging.
- Theoretical predictions align with experimental observations, validating the proposed model.
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