Cooperative and non-cooperative DNA binding modes of catabolite control protein CcpA from Bacillus megaterium result from sensing two different signals
| Autor: | Wolfgang Hillen, Anne Galinier, Roger Gösseringer, Elke Küster, Josef Deutscher |
|---|---|
| Přispěvatelé: | Laboratoire de chimie bactérienne (LCB), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 1997 |
| Předmět: |
DNA
Bacterial Leucine zipper Operator Regions Genetic Operon [SDV]Life Sciences [q-bio] DNA Footprinting DNA Recombinant Catabolite repression Glucose-6-Phosphate Cooperativity Lac repressor 03 medical and health sciences chemistry.chemical_compound Bacterial Proteins Structural Biology [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology Phosphorylation Luciferases Phosphoenolpyruvate Sugar Phosphotransferase System Promoter Regions Genetic Molecular Biology ComputingMilieux_MISCELLANEOUS 030304 developmental biology Bacillus megaterium 0303 health sciences biology 030306 microbiology Cooperative binding Gene Expression Regulation Bacterial Hydrogen-Ion Concentration biology.organism_classification DNA-Binding Proteins Repressor Proteins carbohydrates (lipids) Glucose Biochemistry chemistry Genes Bacterial Mutation CCPA bacteria Electrophoresis Polyacrylamide Gel |
| Zdroj: | Journal of Molecular Biology Journal of Molecular Biology, 1997, 266 (4), pp.665-676. ⟨10.1006/jmbi.1996.0820⟩ Journal of Molecular Biology, Elsevier, 1997, 266 (4), pp.665-676. ⟨10.1006/jmbi.1996.0820⟩ |
| ISSN: | 0022-2836 1089-8638 |
| DOI: | 10.1006/jmbi.1996.0820⟩ |
| Popis: | Carbon catabolite repression (CCR) of several operons in Bacillus subtilis and Bacillus megaterium is mediated by the cis -acting cre sequence and trans -acting catabolite control protein (CcpA). We describe purification of CcpA from B. megaterium and its interaction with regulatory sequences from the xyl operon. Specific interaction of CcpA with cre as scored by DNase I footprints at concentrations similar to the in vivo situation requires the presence of effectors. We have found two molecular effectors for CcpA activity, which lead to different recognition modes of DNA. The heat-stable phosphotransfer protein HPr from the PTS sugar uptake system triggers non-cooperative binding of CcpA to cre when phosphorylated at Ser46 (HPr-Ser46-P). Glucose 6-phosphate (Glc-6-P) triggers cooperative binding of CcpA to cre and two auxiliary cre ∗ sites, one of which overlaps the −35 box of the xyl promoter. Binding to cre∗ depends on the presence of the functional cre sequence. A mutation in cre abolishes carbon catabolite repression in vivo and binding of CcpA to cre and cre ∗ in vitro , indicating looping of the intervening DNA. The two triggers are not simultaneously active. The acidity of the buffer determines which of them activates CcpA when both are present in vitro . Glc-6-P is preferred at pH values below 5.4, and HPr-Ser46-P is preferred at neutral pH. The CcpA dimers present at neutral pH form tetramers and higher oligomers at pH 4.6, explaining cooperativity of binding to DNA. CcpA is the first member of the LacI/GalR family of regulators, for which oligomerization without the leucine zipper at the C terminus is demonstrated. |
| Databáze: | OpenAIRE |
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