7F75

Cryo-EM structure of Spx-dependent transcription activation complex

Summary for 7F75

• Entry DOI: 10.2210/pdb7f75/pdb
• EMDB information: 31485
• Descriptor: DNA-directed RNA polymerase subunit alpha, DNA-directed RNA polymerase subunit delta, MAGNESIUM ION, ... (12 entities in total)
• Functional Keywords: complex, transcription activator, stress, oxidated form, transcription, transcription-dna complex, transcription/dna
• Biological source: Bacillus subtilis; More
• Total number of polymer chains: 12
• Total formula weight: 510067.69

Authors

Lin, W.,Feng, Y.,Shi, J. (deposition date: 2021-06-28, release date: 2021-10-13, Last modification date: 2024-11-13)

Primary citation

Shi, J.,Li, F.,Wen, A.,Yu, L.,Wang, L.,Wang, F.,Jin, Y.,Jin, S.,Feng, Y.,Lin, W.
Structural basis of transcription activation by the global regulator Spx.
Nucleic Acids Res., 49:10756-10769, 2021

PubMed Abstract: Spx is a global transcriptional regulator in Gram-positive bacteria and has been inferred to efficiently activate transcription upon oxidative stress by engaging RNA polymerase (RNAP) and promoter DNA. However, the precise mechanism by which it interacts with RNAP and promoter DNA to initiate transcription remains obscure. Here, we report the cryo-EM structure of an intact Spx-dependent transcription activation complex (Spx-TAC) from Bacillus subtilis at 4.2 Å resolution. The structure traps Spx in an active conformation and defines key interactions accounting for Spx-dependent transcription activation. Strikingly, an oxidized Spx monomer engages RNAP by simultaneously interacting with the C-terminal domain of RNAP alpha subunit (αCTD) and σA. The interface between Spx and αCTD is distinct from those previously reported activators, indicating αCTD as a multiple target for the interaction between RNAP and various transcription activators. Notably, Spx specifically wraps the conserved -44 element of promoter DNA, thereby stabilizing Spx-TAC. Besides, Spx interacts extensively with σA through three different interfaces and promotes Spx-dependent transcription activation. Together, our structural and biochemical results provide a novel mechanistic framework for the regulation of bacterial transcription activation and shed new light on the physiological roles of the global Spx-family transcription factors.

PubMed: 34530448
DOI: 10.1093/nar/gkab790

Experimental method

ELECTRON MICROSCOPY (4.2 Å)