The importance of the interaction of CheD with CheC and the chemoreceptors compared to its enzymatic activity during chemotaxis in Bacillus subtilis.

Bacillus subtilis use three systems for adaptation during chemotaxis. One of these systems involves two interacting proteins, CheC and CheD. CheD binds to the receptors and increases their ability to activate the CheA kinase.

The Bacillus subtilis chemoreceptor McpC senses multiple ligands using two discrete mechanisms.

Bacillus subtilis can perform chemotaxis toward all 20 L-amino acids normally found in proteins. Loss of a single chemoreceptor, McpC, was previously found to reduce chemotaxis to 19 of these amino acids. In this study, we investigated the amino acid-sensing mechanism of McpC.

Elucidation of the multiple roles of CheD in Bacillus subtilis chemotaxis.

Chemotaxis by Bacillus subtilis requires the CheD protein for proper function. In a cheD mutant when McpB was the sole chemoreceptor in B. subtilis, chemotaxis to asparagine was quite good.

Transcriptional cross talk within the mar-sox-rob regulon in Escherichia coli is limited to the rob and marRAB operons.

Bacteria possess multiple mechanisms to survive exposure to various chemical stresses and antimicrobial compounds. In the enteric bacterium Escherichia coli, three homologous transcription factors-MarA, SoxS, and Rob-play a central role in coordinating this response. Three separate systems are known to regulate the expression and activities of MarA, SoxS, and Rob.

Cellular stoichiometry of the chemotaxis proteins in Bacillus subtilis.

The chemoreceptor-CheA kinase-CheW coupling protein complex, with ancillary associated proteins, is at the heart of chemotactic signal transduction in bacteria. The goal of this work was to determine the cellular stoichiometry of the chemotaxis signaling proteins in Bacillus subtilis. Quantitative immunoblotting was used to determine the total number of chemotaxis proteins in a single cell of B.

Attractant binding induces distinct structural changes to the polar and lateral signaling clusters in Bacillus subtilis chemotaxis.

Bacteria employ a modified two-component system for chemotaxis, where the receptors form ternary complexes with CheA histidine kinases and CheW adaptor proteins. These complexes are arranged in semi-ordered arrays clustered predominantly at the cell poles. The prevailing models assume that these arrays are static and reorganize only locally in response to attractant binding.

Site-specific methylation in Bacillus subtilis chemotaxis: effect of covalent modifications to the chemotaxis receptor McpB.

The Bacillus subtilis chemotaxis pathway employs a receptor methylation system that functions differently from the one in the canonical Escherichia coli pathway. Previously, we hypothesized that B. subtilis employs a site-specific methylation system for adaptation where methyl groups are added and removed at different sites.

A PAS domain binds asparagine in the chemotaxis receptor McpB in Bacillus subtilis.

During chemotaxis toward asparagine by Bacillus subtilis, the ligand is thought to bind to the chemoreceptor McpB on the exterior of the cell and induce a conformational change. This change affects the degree of phosphorylation of the CheA kinase bound to the cytoplasmic region of the receptor. Until recently, the sensing domains of the B.

The three adaptation systems of Bacillus subtilis chemotaxis.

Adaptation has a crucial role in the gradient-sensing mechanism that underlies bacterial chemotaxis. The Escherichia coli chemotaxis pathway uses a single adaptation system involving reversible receptor methylation. In Bacillus subtilis, the chemotaxis pathway seems to use three adaptation systems.

The conserved cytoplasmic module of the transmembrane chemoreceptor McpC mediates carbohydrate chemotaxis in Bacillus subtilis.

Escherichia coli cells use two distinct sensory circuits during chemotaxis towards carbohydrates. One circuit requires the phosphoenolpyruvate-dependent phosphotransferase system (PTS) and is independent of any specific chemoreceptor, whereas the other uses a chemoreceptor-dependent sensory mechanism analogous to that used during chemotaxis towards amino acids. Work on the carbohydrate chemotaxis sensory circuit of Bacillus subtilis reported in this article indicates that the B.