Region 2.1 of the Escherichia coli heat-shock sigma factor RpoH (σ 32) is necessary but not sufficient for degradation by the FtsH protease
| Autor: | Regine Hengge, Markus Obrist, Eberhard Klauck, Franz Narberhaus, Sonja Milek |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Recombinant Fusion Proteins
medicine.medical_treatment Proteolysis Sigma Factor medicine.disease_cause Microbiology ATP-Dependent Proteases Bacterial Proteins Sigma factor Escherichia coli medicine HSP70 Heat-Shock Proteins Bradyrhizobium Heat-Shock Proteins chemistry.chemical_classification Protease biology medicine.diagnostic_test Escherichia coli Proteins HSP40 Heat-Shock Proteins biology.organism_classification Enterobacteriaceae Protein Structure Tertiary Amino acid Biochemistry chemistry bacteria rpoS Protein Binding Bradyrhizobium japonicum |
| Zdroj: | Microbiology. 153:2560-2571 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/mic.0.2007/007047-0 |
| Popis: | The cellular level of the Escherichia coli heat-shock sigma factor RpoH (sigma32) is negatively controlled by chaperone-mediated proteolysis through the essential metalloprotease FtsH. Point mutations in the highly conserved region 2.1 stabilize RpoH in vivo. To assess the importance of this turnover element, hybrid proteins were constructed between E. coli RpoH and Bradyrhizobium japonicum RpoH1, a stable RpoH protein that differs from region 2.1 of E. coli RpoH at several positions. Nine amino acids forming a putative alpha-helix were exchanged between the two proteins. Both hybrids were active sigma factors and showed intermediate protein stability. Introduction of RpoH region 2.1 into the general stress sigma factor RpoS, which is a substrate of the ClpXP protease, did not render RpoS susceptible to FtsH. Hence, region 2.1 alone is not sufficient to confer FtsH sensitivity to other proteins. Region 2.1 is not a major chaperone-binding site since DnaK and DnaJ bound efficiently to all RpoH variants. The in vivo stability of the mutated RpoH proteins correlated with their stability in a purified in vitro degradation system, suggesting that region 2.1 might be directly involved in the interaction with the FtsH protease. |
| Databáze: | OpenAIRE |
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