Meier, Veronika M. and Muschler, Paul and Scharf, Scharf (2007) Functional analysis of nine putative chemoreceptor proteins in Sinorhizobium meliloti. JOURNAL OF BACTERIOLOGY, 189 (5). pp. 1816-1826. ISSN 0021-9193,
Full text not available from this repository. (Request a copy)Abstract
The genome of the symbiotic soil bacterium Sinorhizobium meliloti contains eight genes coding for methyl-accepting chemotaxis proteins (MCPs) McpS to McpZ and one gene coding for a transducer-like protein, IcpA. Seven of the MCPs are localized in the cytoplasmic membrane via two membrane-spanning regions, whereas McpY and IcpA lack such hydrophobic regions. The periplasmic regions of McpU, McpV, and McpX contain the small-ligand-binding domain Cache. In addition, McpU possesses the ligand-binding domain TarH. By probing gene expression with lacZ fusions, we have identified mepU and mepX as being highly expressed. Deletion of any one of the receptor genes caused impairments in the chemotactic response toward most organic acids, amino acids, and sugars in a swarm plate assay. The data imply that chemoreceptor proteins in S. meliloti can sense more than one class of carbon source and suggest that many or all receptors work as an ensemble. Tactic responses were virtually eliminated for a strain lacking all nine receptor genes. Capillary assays revealed three important sensors for the strong attractant proline: McpU, McpX, and McpY. Receptor deletions variously affected free-swimming speed and attractant-induced chemokinesis. Noticeably, cells lacking mepU were swimming 9% slower than the wild-type control. We infer that McpU inhibits the kinase activity of CheA in the absence of an attractant. Cells lacking one of the two soluble receptors were impaired in chemokinetic proficiency by more than 50%. We propose that the internal sensors, IcpA and the PAS domain containing McpY, monitor the metabolic state of S. meliloti.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | RHIZOBIUM-LUPINI H13-3; BACTERIAL FLAGELLAR MOTOR; GRAM-NEGATIVE BACTERIA; ESCHERICHIA-COLI; SIGNAL-TRANSDUCTION; ADAPTATIONAL DEMETHYLATION; CAULOBACTER-CRESCENTUS; FILAMENT STRUCTURE; GENOME SEQUENCE; MOTILITY GENES; |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 21 Dec 2020 13:22 |
| Last Modified: | 21 Dec 2020 13:22 |
| URI: | https://pred.uni-regensburg.de/id/eprint/33107 |
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