pH Sensing in Bacterial Chemotaxis

摘要: Bacteria are able to sense a broad range of chemical and energetic stimuli modulate their swimming behaviour migrate more favourable environments. Signal transduction in bacterial chemotaxis is mediated by two-component system composed protein histidine kinase, CheA, response regulator, CheY. The phosphorylated P approximately CheY, binds at the flagellar motor, FliM, cause reversals motor rotation. level CheY controlled activity kinase which turn regulated membrane receptors cell surface. Membrane such as aspartate receptor, Tar, two distinct regions: an extracellular sensing domain that stimulatory ligands, case Tar; intracellular signalling forms complex with CheA. What mechanism transmembrane signalling? How does binding outside surface translate into change cytosol interface? Recent results suggest depends on perturbations lateral packing within extensive array localized patches poles. Receptor patching appears depend higher-order associations CheA well adaptor protein, CheW. It difficult assess locus pH effects context even simple signal like involved chemotaxis. Previous mutant strains have indicated serine Tsr, critical for sensing, but vitro do not support straightforward interpretation genetic data.