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ATP-dependent active transport simulations based on a phosphatase-channel-kinase membrane structure
K Fiaty1, C Charcosset, B Perrin
1Laboratoire d'Automatique et de Génie des Procédés, UMR-CNRS 5007, CPE Lyon, Université Claude Bernard Lyon 1, Bat 308 G, 43 Bd du 11 novembre 1918, 69622 Villeurbanne cedex, France.
Journal of Computational Chemistry
|May 13, 2004
Summary
This study shows a phosphatase-channel-kinase (PCK) topology enables active transport of phosphorylated substrates. With added phosphatase activity, it also actively transports unphosphorylated substrates across membranes.
Area of Science:
- Biophysics
- Membrane Transport
- Computational Biology
Background:
- Enzymatic reactions, diffusion, and electrostatics are key to membrane transport.
- A phosphatase-channel-kinase (PCK) topology was previously shown to facilitate active transport of phosphorylated substrates.
Purpose of the Study:
- To investigate if the PCK topology can also facilitate active transport of unphosphorylated substrates.
- To develop a general mathematical model for analyzing these transport phenomena under various conditions.
Main Methods:
- Simulations of coupled enzymatic reaction-diffusion-electrostatic interactions.
- Analysis of a fixed PCK topology across a charged membrane.
- Mathematical modeling of substrate transport with and without inner-side phosphatase activity.
Main Results:
- The PCK topology alone actively transports phosphorylated substrates.
- The PCK topology, with an additional inner-side phosphatase, actively transports unphosphorylated substrates.
- The model accounts for ATP consumption and varying substrate charges.
Conclusions:
- The PCK membrane topology acts as a versatile ATP-dependent transporter for both phosphorylated and unphosphorylated substrates.
- The study defines physicochemical conditions and membrane configurations for optimal active transport.
- This general model provides insights into active transport mechanisms across charged membranes.