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Title | Structural basis of transcriptional activation by the Mycobacterium tuberculosis intrinsic antibiotic-resistance transcription factor WhiB7. |
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Journal, issue, pages | Mol Cell, Vol. 81, Issue 14, Page 2875-22886.e5, Year 2021 |
Publish date | Jul 15, 2021 |
Authors | Mirjana Lilic / Seth A Darst / Elizabeth A Campbell / |
PubMed Abstract | In pathogenic mycobacteria, transcriptional responses to antibiotics result in induced antibiotic resistance. WhiB7 belongs to the Actinobacteria-specific family of Fe-S-containing transcription ...In pathogenic mycobacteria, transcriptional responses to antibiotics result in induced antibiotic resistance. WhiB7 belongs to the Actinobacteria-specific family of Fe-S-containing transcription factors and plays a crucial role in inducible antibiotic resistance in mycobacteria. Here, we present cryoelectron microscopy structures of Mycobacterium tuberculosis transcriptional regulatory complexes comprising RNA polymerase σ-holoenzyme, global regulators CarD and RbpA, and WhiB7, bound to a WhiB7-regulated promoter. The structures reveal how WhiB7 interacts with σ-holoenzyme while simultaneously interacting with an AT-rich sequence element via its AT-hook. Evidently, AT-hooks, rare elements in bacteria yet prevalent in eukaryotes, bind to target AT-rich DNA sequences similarly to the nuclear chromosome binding proteins. Unexpectedly, a subset of particles contained a WhiB7-stabilized closed promoter complex, revealing this intermediate's structure, and we apply kinetic modeling and biochemical assays to rationalize how WhiB7 activates transcription. Altogether, our work presents a comprehensive view of how WhiB7 serves to activate gene expression leading to antibiotic resistance. |
External links | Mol Cell / PubMed:34171296 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.74 - 3.38 Å |
Structure data | EMDB-22886, PDB-7kif: EMDB-22887, PDB-7kim: EMDB-22888, PDB-7kin: |
Chemicals | ChemComp-ZN: ChemComp-MG: ChemComp-SF4: |
Source |
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Keywords | TRANSCRIPTION / TRANSFERASE/DNA / RNA polymerase / Transcription factor / Mycobacterium tuberculosis / Iron cluster / TRANSFERASE-DNA complex |