6KJ6

cryo-EM structure of Escherichia coli Crl transcription activation complex

Summary for 6KJ6

• Entry DOI: 10.2210/pdb6kj6/pdb
• EMDB information: 0700
• Descriptor: DNA-directed RNA polymerase subunit alpha, ZINC ION, MAGNESIUM ION, ... (11 entities in total)
• Functional Keywords: rna polymerase, escherichia coli, crl, transcription activation, transcription initiation, transcription regulator, sigma s, transcription
• Biological source: Escherichia coli K-12; More
• Total number of polymer chains: 10
• Total formula weight: 478381.70

Authors

Xu, J.,Zhang, Y. (deposition date: 2019-07-21, release date: 2020-01-01, Last modification date: 2024-03-27)

Primary citation

Xu, J.,Cui, K.,Shen, L.,Shi, J.,Li, L.,You, L.,Fang, C.,Zhao, G.,Feng, Y.,Yang, B.,Zhang, Y.
Crl activates transcription by stabilizing active conformation of the master stress transcription initiation factor.
Elife, 8:-, 2019

PubMed Abstract: σ is a master transcription initiation factor that protects bacterial cells from various harmful environmental stresses including antibiotic pressure. Although its mechanism remains unclear, it is known that full activation of σ-mediated transcription requires a σ-specific activator, Crl. In this study, we determined a 3.80 Å cryo-EM structure of an transcription activation complex ( Crl-TAC) comprising σ-RNA polymerase (σ-RNAP) holoenzyme, Crl, and a nucleic-acid scaffold. The structure reveals that Crl interacts with domain 2 of σ (σ) and the RNAP core enzyme, but does not contact promoter DNA. Results from subsequent hydrogen-deuterium exchange mass spectrometry (HDX-MS) indicate that Crl stabilizes key structural motifs within σ to promote the assembly of the σ-RNAP holoenzyme and also to facilitate formation of an RNA polymerase-promoter DNA open complex (RPo). Our study demonstrates a unique DNA contact-independent mechanism of transcription activation, thereby defining a previously unrecognized mode of transcription activation in cells.

PubMed: 31846423
DOI: 10.7554/eLife.50928

Experimental method

ELECTRON MICROSCOPY (3.8 Å)