The bacterial flagellar motor is capable of adapting to changes in the concentrations of extracellular chemical stimuli by changing the composition of the switch complex of the flagellar motor. Such remodeling-based adaptation complements the receptor-mediated adaptation in the chemotaxis network to help maintain high sensitivity in the response of the motor to phospho-CheY concentrations, despite cell-to-cell variability in the abundances of chemotaxis proteins. In this chapter, a modeling approach is described that explains the mechanisms of switch-remodeling and motor-mediated adaptation. The approach is based on observations of structural differences, associated with the direction of motor rotation, that modulate the strength of FliM/FliN binding within the switch. By modulating the number of CheY-P-binding sites within the motor, remodeling maximizes sensitivity over a range of signal levels.
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This work was supported by funds from Texas A&M Engineering Experiment Station. The PI acknowledges support from the National Institute Of General Medical Sciences of the National Institutes of Health under Award Number R01GM123085. The content is solely the responsibility of the author and does not necessarily represent the official views of the National Institutes of Health.
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