7XYB

The cryo-EM structure of an AlpA-loaded complex

Summary for 7XYB

• Entry DOI: 10.2210/pdb7xyb/pdb
• EMDB information: 33516
• Descriptor: DNA-directed RNA polymerase subunit alpha, DNA-directed RNA polymerase subunit beta, DNA-directed RNA polymerase subunit beta', ... (9 entities in total)
• Functional Keywords: antitermination, rna polymerase, transcription regulation, antiterminator, transcription termination, transcription
• Biological source: Pseudomonas aeruginosa; More
• Total number of polymer chains: 9
• Total formula weight: 462487.95

Authors

Wen, A.,Feng, Y. (deposition date: 2022-06-01, release date: 2022-07-20, Last modification date: 2024-10-16)

Primary citation

Wen, A.,Zhao, M.,Jin, S.,Lu, Y.Q.,Feng, Y.
Structural basis of AlpA-dependent transcription antitermination.
Nucleic Acids Res., 50:8321-8330, 2022

PubMed Abstract: AlpA positively regulates a programmed cell death pathway linked to the virulence of Pseudomonas aeruginosa by recognizing an AlpA binding element within the promoter, then binding RNA polymerase directly and allowing it to bypass an intrinsic terminator positioned downstream. Here, we report the single-particle cryo-electron microscopy structures of both an AlpA-loading complex and an AlpA-loaded complex. These structures indicate that the C-terminal helix-turn-helix motif of AlpA binds to the AlpA binding element and that the N-terminal segment of AlpA forms a narrow ring inside the RNA exit channel. AlpA was also revealed to render RNAP resistant to termination signals by prohibiting RNA hairpin formation in the RNA exit channel. Structural analysis predicted that AlpA, 21Q, λQ and 82Q share the same mechanism of transcription antitermination.

PubMed: 35871295
DOI: 10.1093/nar/gkac608

Experimental method

ELECTRON MICROSCOPY (3.7 Å)