Publication Date:
2015-10-18
Description:
Stimulation of Escherichia coli by exponential ramps of chemoattractants generates step changes in the concentration of the response regulator, CheY-P. Because flagellar motors are ultrasensitive, this should change the fraction of time that motors spin clockwise, the CW bias . However, early work failed to show changes in CW bias when ramps were shallow. This was explained by a model for motor remodeling that predicted plateaus in plots of CW bias versus [CheY-P]. We looked for these plateaus by examining distributions of CW bias in populations of cells with different mean [CheY-P]. We did not find such plateaus. Hence, we repeated the work on shallow ramps and found that motors did indeed respond. These responses were quantitatively described by combining motor remodeling with ultrasensitivity in a model that exhibited high sensitivities over a wide dynamic range.
Electronic ISSN:
2375-2548
Topics:
Natural Sciences in General
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