EMD-36914
Cryo-EM structure of Streptomyces coelicolor transcription initiation complex with the global transcription factor AfsR
EMD-36914
Single-particle3.4 Å
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Map released: 31/07/2024
Last modified: 21/08/2024
Sample Organism:
Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)
Sample: Streptomyces coelicolor transcription initiation complex with the global transcription factor AfsR
Fitted models: 8k60 (Avg. Q-score: 0.447)
Deposition Authors: Lin W, Shi J, Xu JC
Sample: Streptomyces coelicolor transcription initiation complex with the global transcription factor AfsR
Fitted models: 8k60 (Avg. Q-score: 0.447)
Deposition Authors: Lin W, Shi J, Xu JC
Structural insights into transcription activation of the Streptomyces antibiotic regulatory protein, AfsR.
Shi J,
Ye Z,
Feng Z,
Wen A,
Wang L,
Zhang Z,
Xu L,
Song Q,
Wang F,
Liu T,
Wang S,
Feng Y,
Lin W
(2024) iScience , 27 , 110421 - 110421
(2024) iScience , 27 , 110421 - 110421
Abstract:
The Streptomyces antibiotic regulatory proteins (SARPs) are ubiquitously distributed transcription activators in Streptomyces and control antibiotics biosynthesis and morphological differentiation. However, the molecular mechanism behind SARP-dependent transcription initiation remains elusive. We here solve the cryo-EM structure of an AfsR-loading RNA polymerase (RNAP)-promoter intermediate complex (AfsR-RPi) including the Streptomyces coelicolor RNAP, a large SARP member AfsR, and its target promoter DNA that retains the upstream portion straight. The structure reveals that one dimeric N-terminal AfsR-SARP domain (AfsR-SARP) specifically engages with the same face of the AfsR-binding sites by the conserved DNA-binding domains (DBDs), replacing σHrdBR4 to bind the suboptimal -35 element, and shortens the spacer between the -10 and -35 elements. Notably, the AfsR-SARPs also recruit RNAP through extensively interacting with its conserved domains (β flap, σHrdBR4, and αCTD). Thus, these macromolecular snapshots support a general model and provide valuable clues for SARP-dependent transcription activation in Streptomyces.
The Streptomyces antibiotic regulatory proteins (SARPs) are ubiquitously distributed transcription activators in Streptomyces and control antibiotics biosynthesis and morphological differentiation. However, the molecular mechanism behind SARP-dependent transcription initiation remains elusive. We here solve the cryo-EM structure of an AfsR-loading RNA polymerase (RNAP)-promoter intermediate complex (AfsR-RPi) including the Streptomyces coelicolor RNAP, a large SARP member AfsR, and its target promoter DNA that retains the upstream portion straight. The structure reveals that one dimeric N-terminal AfsR-SARP domain (AfsR-SARP) specifically engages with the same face of the AfsR-binding sites by the conserved DNA-binding domains (DBDs), replacing σHrdBR4 to bind the suboptimal -35 element, and shortens the spacer between the -10 and -35 elements. Notably, the AfsR-SARPs also recruit RNAP through extensively interacting with its conserved domains (β flap, σHrdBR4, and αCTD). Thus, these macromolecular snapshots support a general model and provide valuable clues for SARP-dependent transcription activation in Streptomyces.