The role of C-terminal extensions in controlling ECF σ factor activity in the widely conserved groups ECF41 and ECF42
| Autor: | Franziska Dürr, Delia Casas-Pastor, Georg Fritz, Hao Wu, Qiang Liu, Thorsten Mascher |
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| Rok vydání: | 2019 |
| Předmět: |
Models
Molecular Subfamily Protein domain Amino Acid Motifs Sequence alignment Sigma Factor Computational biology Biology Microbiology Conserved sequence 03 medical and health sciences Bacterial Proteins Amino Acid Sequence Promoter Regions Genetic Molecular Biology Peptide sequence Conserved Sequence Phylogeny 030304 developmental biology Alanine 0303 health sciences Bacteria 030306 microbiology Gene Expression Regulation Bacterial Tetratricopeptide Sequence Alignment Function (biology) |
| Zdroj: | Molecular microbiologyReferences. 112(2) |
| ISSN: | 1365-2958 |
| Popis: | The activity of extracytoplasmic function σ-factors (ECFs) is typically regulated by anti-σ factors. In a number of highly abundant ECF groups, including ECF41 and ECF42, σ-factors contain fused C-terminal protein domains, which provide the necessary regulatory function instead. Here, we identified the contact interface between the C-terminal extension and the core σ-factor regions required for controlling ECF activity. We applied direct coupling analysis (DCA) to infer evolutionary covariation between contacting amino acid residues for groups ECF41 and ECF42. Mapping the predicted interactions to a recently solved ECF41 structure demonstrated that DCA faithfully identified an important contact interface between the SnoaL-like extension and the linker between the σ2 and σ4 domains. Systematic alanine substitutions of contacting residues support this model and suggest that this interface stabilizes a compact conformation of ECF41 with low transcriptional activity. For group ECF42, DCA supports a structural homology model for their C-terminal tetratricopeptide repeat (TPR) domains and predicts an intimate contact between the first TPR-helix and the σ4 domain. Mutational analyses demonstrate the essentiality of the predicted interactions for ECF42 activity. These results indicate that C-terminal extensions indeed bind and regulate the core ECF regions, illustrating the potential of DCA for discovering regulatory motifs in the ECF subfamily. |
| Databáze: | OpenAIRE |
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