S-Space College of Medicine/School of Medicine (의과대학/대학원) Immunology (면역학전공) Journal Papers (저널논문_면역학전공)
The multi-step phosphorelay mechanism of unorthodox two-component systems in E. coli realizes ultrasensitivity to stimuli while maintaining robustness to noises
- Issue Date
- Comput Biol Chem. 2006 Dec;30(6):438-44. Epub 2006 Nov 16.
- Cell Survival ; Computer Simulation ; Escherichia coli/chemistry/*metabolism ; Escherichia coli Proteins/*metabolism ; Histidine/*metabolism ; Mathematics ; Phosphorylation ; Protein Kinases/*metabolism ; Noise ; Signal Transduction
- E. coli has two-component systems composed of histidine kinase proteins and response regulator proteins. For a given extracellular stimulus, a histidine kinase senses the stimulus, autophosphorylates and then passes the phosphates to the cognate response regulators. The histidine kinase in an orthodox two-component system has only one histidine domain where the autophosphorylation occurs, but a histidine kinase in some unusual two-component systems (unorthodox two-component systems) has two histidine domains and one aspartate domain. So, the unorthodox two-component systems have more complex phosphorelay mechanisms than orthodox two-component systems. In general, the two-component systems are required to promptly respond to external stimuli for survival of E. coli. In this respect, the complex multi-step phosphorelay mechanism seems to be disadvantageous, but there are several unorthodox two-component systems in E. coli. In this paper, we investigate the reason why such unorthodox two-component systems are present in E. coli. For this purpose, we have developed simplified mathematical models of both orthodox and unorthodox two-component systems and analyzed their dynamical characteristics through extensive computer simulations. We have finally revealed that the unorthodox two-component systems realize ultrasensitive responses to external stimuli and also more robust responses to noises than the orthodox two-component systems.
- 1476-9271 (Print)
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