Myriad Molecules in Motion: Simulated Diffusion as a New Tool To Study Molecular Movement and Interaction in a Living Cell
| Autor: | Gerald L. Hazelbauer |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Cytoplasm
Movement (music) Escherichia coli Proteins Chemotaxis Membrane Proteins Methyl-Accepting Chemotaxis Proteins Meeting Presentations Living cell Biology Microbiology Motion (physics) Diffusion Bacterial protein Bacterial Proteins Biochemistry Escherichia coli Computer Simulation Guest Commentaries Phosphorylation Diffusion (business) Biological system Molecular Biology Signal Transduction |
| Zdroj: | Journal of Bacteriology. 187:23-25 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.187.1.23-25.2005 |
| Popis: | We describe the use of a computational model to study the effects of cellular architecture and macromolecular crowding on signal transduction in Escherichia coli chemotaxis. A newly developed program, Smoldyn, allows the movement and interaction of a large number of individual molecules in a structured environment to be simulated (S. S. Andrews and D. Bray, Phys. Biol., in press). With Smoldyn, we constructed a three-dimensional model of an E. coli cell and examined the diffusion of CheYp from the cluster of receptors to the flagellar motors under control conditions and in response to attractant and repellent stimuli. Our simulations agree well with experimental observations of cell swimming responses and are consistent with the diffusive behavior expected in wild-type and mutant cells. The high resolution available to us in the new program allows us to calculate the loci of individual CheYp molecules in a cell and the distribution of their lifetimes under different cellular conditions. We find that the time delay between stimulus and response differs for flagellar motors located at different positions in the cell. We explore different possible locations for the phosphatase CheZ and show conditions under which a gradient of CheYp exists in the cell. The introduction of inert blocks into the cytoplasm, representing impenetrable structures such as the nucleoid and large protein complexes, produces a fall in the apparent diffusion coefficient of CheYp and enhances the differences between motors. These and other results are left as predictions for future experiments. |
| Databáze: | OpenAIRE |
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