Scharf, Birgit and Schmitt, Ruediger (2002) Sensory transduction to the flagellar motor of Sinorhizobium meliloti. JOURNAL OF MOLECULAR MICROBIOLOGY AND BIOTECHNOLOGY, 4 (3). pp. 183-186. ISSN 1464-1801
Full text not available from this repository.Abstract
Molecular mechanisms that govern chemotaxis and motility in the nitrogen-fixing soil bacterium, Sinorhizobium meliloti, are distinguished from the well-studied taxis systems of enterobacteria by new features. (i) In addition to six transmembrane chemotaxis receptors, S. meliloti has two cytoplasmic receptor proteins, McpY (methyl-accepting chemotaxis protein) and IcpA (internal chemotaxis protein). (ii) The tactic response is mediated by two response regulators, CheY1 and CheY2, but no phosphatase, CheZ. Phosphorylated CheY2 (CheY2-P) is the main regulator of motor function, whereas CheY1 assumes the role of a 'sink' for phosphate that is shuttled from CheY2-P back to CheA. This phospho-transfer from surplus CheY2-P to CheA to CheY1 replaces CheZ phosphatase. (iii) S. meliloti flagella have a complex structure with three helical ribbons that render the filaments rigid and unable to undergo polymorphic transitions from right- to left-handedness. Flagella rotate only clockwise and their motors can increase and decrease rotary speed. Hence, directional changes of a swimming cell occur during slow-down, when several flagella rotate at different speed. Two novel motility proteins, the periplasmic MotC and the cytoplasmic MotD, are essential for motility and rotary speed variation. A model consistent with these data postulates a MotC-mediated gating of the energizing MotA-MotB proton channels leading to variations in flagellar rotary speed.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | RHIZOBIUM-MELILOTI; SIGNAL-TRANSDUCTION; COMPLEX FLAGELLA; MOTILITY GENES; CHEMOTAXIS; REGULATORS; OPERON; OXYGEN; CHEY1; |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 27 Oct 2021 06:55 |
| Last Modified: | 27 Oct 2021 06:55 |
| URI: | https://pred.uni-regensburg.de/id/eprint/40344 |
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