6OMF
CryoEM structure of SigmaS-transcription initiation complex with activator Crl
Summary for 6OMF
| Entry DOI | 10.2210/pdb6omf/pdb |
| EMDB information | 20090 |
| Descriptor | DNA-directed RNA polymerase subunit alpha, ZINC ION, DNA-directed RNA polymerase subunit beta, ... (10 entities in total) |
| Functional Keywords | transcription-activator, dna/rna, sigmas, beta', transcription, transferase-dna complex, transferase/dna |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 9 |
| Total formula weight | 464375.79 |
| Authors | Jaramillo Cartagena, A.,Darst, S.A.,Campbell, E.A. (deposition date: 2019-04-18, release date: 2019-08-28, Last modification date: 2024-03-13) |
| Primary citation | Cartagena, A.J.,Banta, A.B.,Sathyan, N.,Ross, W.,Gourse, R.L.,Campbell, E.A.,Darst, S.A. Structural basis for transcription activation by Crl through tethering of sigmaSand RNA polymerase. Proc.Natl.Acad.Sci.USA, 116:18923-18927, 2019 Cited by PubMed Abstract: In bacteria, a primary σ-factor associates with the core RNA polymerase (RNAP) to control most transcription initiation, while alternative σ-factors are used to coordinate expression of additional regulons in response to environmental conditions. Many alternative σ-factors are negatively regulated by anti-σ-factors. In , , and many other γ-proteobacteria, the transcription factor Crl positively regulates the alternative σ-regulon by promoting the association of σ with RNAP without interacting with promoter DNA. The molecular mechanism for Crl activity is unknown. Here, we determined a single-particle cryo-electron microscopy structure of Crl-σ-RNAP in an open promoter complex with a σ-regulon promoter. In addition to previously predicted interactions between Crl and domain 2 of σ (σ), the structure, along with -benzoylphenylalanine cross-linking, reveals that Crl interacts with a structural element of the RNAP β'-subunit that we call the β'-clamp-toe (β'CT). Deletion of the β'CT decreases activation by Crl without affecting basal transcription, highlighting the functional importance of the Crl-β'CT interaction. We conclude that Crl activates σ-dependent transcription in part through stabilizing σ-RNAP by tethering σ and the β'CT. We propose that Crl, and other transcription activators that may use similar mechanisms, be designated σ-activators. PubMed: 31484766DOI: 10.1073/pnas.1910827116 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.26 Å) |
Structure validation
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