An active role for a structured B-linker in effector control of the sigma54-dependent regulator DmpR
| Autor: | P M Wikström, Victoria Shingler, Eric O'Neill |
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| Rok vydání: | 2001 |
| Předmět: |
Repetitive Sequences
Amino Acid Transcriptional Activation Molecular Sequence Data Mutant Allosteric regulation Regulator Sigma Factor Biology DNA-binding protein Article General Biochemistry Genetics and Molecular Biology Bacterial Proteins Sigma factor Transcription (biology) Amino Acid Sequence Molecular Biology Psychological repression Adenosine Triphosphatases Sequence Homology Amino Acid General Immunology and Microbiology Effector General Neuroscience DNA-Directed RNA Polymerases DNA-Binding Proteins Biochemistry Trans-Activators RNA Polymerase Sigma 54 |
| Zdroj: | The EMBO Journal. 20:819-827 |
| ISSN: | 1460-2075 |
| Popis: | The activities of many prokaryotic sigma54-dependent transcriptional activators are controlled by the N-terminal A-domain of the protein, which is linked to the central transcriptional activation domain via a short B-linker. It used to be thought that these B-linkers simply serve as flexible tethers. Here we show that the B-linker of the aromatic-responsive regulator DmpR and many other regulators of the family contain signature heptad repeats with regularly spaced hydrophobic amino acids. Mutant analysis of this region of DmpR demonstrates that B-linker function is dependent on the heptad repeats and is critical for activation of the protein by aromatic effectors. The phenotypes of DmpR mutants refute the existing model that the level of ATPase activity directly controls the level of transcription it promotes. The mutant analysis also shows that the B-linker is involved in repression of ATPase activity and that allosteric changes upon effector binding are transduced to alleviate both B-linker repression of ATP hydrolysis and A-domain repression of transcriptional activation. The mechanistic implications of these findings for DmpR and other family members are discussed. |
| Databáze: | OpenAIRE |
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