Riepl, Hubert and Maurer, Till and Kalbitzer, Hans Robert and Meier, Veronika M. and Haslbeck, Martin and Schmitt, Ruediger and Scharf, Birgit (2008) Interaction of CheY2 and CheY2-P with the cognate CheA kinase in the chemosensory-signalling chain of Sinorhizobium meliloti. MOLECULAR MICROBIOLOGY, 69 (6). pp. 1373-1384. ISSN 0950-382X,
Full text not available from this repository. (Request a copy)Abstract
An unusual regulatory mechanism involving two response regulators, CheY1 and CheY2, but no CheZ phosphatase, operates in the chemotactic signalling chain of Sinorhizobium meliloti. Active CheY2-P, phosphorylated by the cognate histidine kinase, CheA, is responsible for flagellar motor control. In the absence of any CheZ phosphatase activity, the level of CheY2-P is quickly reset by a phospho-transfer from CheY2-P first back to CheA, and then to CheY1, which acts as a phosphate sink. In studying the mechanism of this phosphate shuttle, we have used GFP fusions to show that CheY2, but not CheY1, associates with CheA at a cell pole. Cross-linking experiments with the purified proteins revealed that both CheY2 and CheY2-P bind to an isolated P2 ligand-binding domain of CheA, but CheY1 does not. The dissociation constants of CheA-CheY2 and CheA-CheY2-P indicated that both ligands bind with similar affinity to CheA. Based on the NMR structures of CheY2 and CheY2-P, their interactions with the purified P2 domain were analysed. The interacting surface of CheY2 comprises its C-terminal beta 4-alpha 4-beta 5-alpha 5 structural elements, whereas the interacting surface of CheY2-P is shifted towards the loop connecting beta 5 and alpha 5. We propose that the distinct CheY2 and CheY2-P surfaces interact with two overlapping sites in the P2 domain that selectively bind either CheY2 or CheY2-P, depending on whether CheA is active or inactive.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOSPHORYLATION-DEPENDENT BINDING; BACTERIAL CHEMOTAXIS; RHIZOBIUM-MELILOTI; RHODOBACTER-SPHAEROIDES; CHEMORECEPTOR COMPLEX; RESPONSE REGULATORS; SECONDARY STRUCTURE; PROTEIN; PHOSPHOTRANSFER; TRANSDUCTION; |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie > Prof. Dr. Dr. Hans Robert Kalbitzer Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Cell Cycle Control > Prof. Dr. Wolfgang Seufert |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 26 Oct 2020 09:49 |
| Last Modified: | 26 Oct 2020 09:49 |
| URI: | https://pred.uni-regensburg.de/id/eprint/30406 |
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