Fine tuned model for perfect adaptation spiro et a1.PNAs94,7263-7268(1997) A model of excitation and adaptation in bacterial chemotaxis
‘Fine tuned model for perfect adaptation’ Spiro et al. PNAS 94, 7263-7268 (1997) A model of excitation and adaptation in bacterial chemotaxis
+ATT flagellar +cH3-8 motor MCPs MCPs CW PA--CHa ATP ATP ADP Z B (YP, Figure 1 of Spiro, P. A, J.S. Parkinson, and H. G. Othmer A model of excitation and adaptation in bacterial chemotaxis Proc Nat/ Acad SciU sA 94, no 14 Jul 8, 1997):7263-8 Copyright (1997) National Academy of Sciences, U.S.A key player: Tar-CheA-CheW complex
key player: Tar-CheA-CheW complex Copyright (1997) National Academy of Sciences, U. S. A. Figure 1 of Spiro, P. A., J. S. Parkinson, and H. G. Othmer. Proc Natl Acad Sci U S A 94, no. 14 (Jul 8, 1997): 7263-8. "A model of excitation and adaptation in bacterial chemotaxis
assumptions 1. Tar is only receptor type, chew and cheA a lways bound to tar 2. Methylation occurs in specific order 3. Consider only 3 highest methylation states 4. Only cheB demethylate 5. Phoshorylation of chea does not affect ligand (un)binding 6. Tar-cher binding does not affect ligand un (binding) and phosphorylation of cheA Chez is not regulated 8. Phosphotransfer from complex to CheY or Cheb is not affected by occupancy or methylation state
assumptions: 1. Tar is only receptor type, CheW and CheA always bound to Tar 2. Methylation occurs in specific order 3. Consider only 3 highest methylation states 4. Only CheBp demethylates 5. Phoshorylation of CheA does not affect ligand (un)binding 6. Tar-CheR binding does not affect ligand un(binding) and phosphorylation of CheA 7. CheZ is not regulated 8. Phosphotransfer from complex to CheY or CheB is not affected by occupancy or methylation state
Phosphorylation Methylation gand e Binding七e ,+SlowT34-T fast A Y B B Figure 2 of Spiro, P. A, J.S. Parkinson, and H. G. Othmer A model of excitation and adaptation in bacterial chemotaxis Proc Nat/ Acad SciUSA 94, no 14 (Jul 8, 1997): 7263-8
fast slow intermediate Copyright (1997) National Academy of Sciences, U. S. A. Figure 2 of Spiro, P. A., J. S. Parkinson, and H. G. Othmer. Proc Natl Acad Sci U S A 94, no. 14 (Jul 8, 1997): 7263-8. "A model of excitation and adaptation in bacterial chemotaxis
Ligand bound states generally have lower autophosphorylation rates Phosphorylation Methylation igan Binding 4p 2 p -LI 3p 3 Figure 2 of Spiro, P. A, J S Parkinson, and H. G Othmer A model of excitation and adaptation in bacterial chemotaxis Proc Nat/ Acad Sci UsA94, no 14(Jul 8, 1997): 7263-8
Ligand bound states generally have lower autophosphoryalation rates Copyright (1997) National Academy of Sciences, U. S. A. Copyright (1997) National Academy of Sciences, U. S. A. Figure 2 of Spiro, P. A., J. S. Parkinson, and H. G. Othmer. Proc Natl Acad Sci U S A 94, no. 14 (Jul 8, 1997): 7263-8. "A model of excitation and adaptation in bacterial chemotaxis