Modelling Sensory Adaptation of Chemotaxis in Bacillus subtilis

Freek J.H. de Haas (2015) Modelling Sensory Adaptation of Chemotaxis in Bacillus subtilis. Master's Thesis / Essay, Biology.

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Abstract

Exact sensory adaptation, the return of membrane receptors to prestimulus activity, is crucial to perform chemotaxis over a wider range of ligand concentrations. Three sensory adaptation systems were identi_ed in Bacillus subtilis, two of which are at the focus of this study: (1) the methylation system afects receptor activity by adding and removing methyl groups and (2) the CheC-CheD-CheYp system by regulating CheD binding to the receptor. However their mechanisms are unclear. In this study we modeled three hypothetical mechanisms and analyzed their contribution to sensory adaptation. We showed that shuttling dynamics between site Glu630 and Glu637 of the McpB receptor can result in exact sensory adaptation, only if methylation rates are activity- and site-dependent. We also tested two mechanisms to dissociate CheD from the receptor, (1) either through its interactions with a methylation site or (2) through an increase in a_nity for the alternative binding site CheC. Interestingly, both hypotheses suggest that the role of CheD as a receptor activator is negligible.

Item Type:	Thesis (Master's Thesis / Essay)
Degree programme:	Biology
Thesis type:	Master's Thesis / Essay
Language:	English
Date Deposited:	15 Feb 2018 08:10
Last Modified:	15 Feb 2018 08:10
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/13604

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