Skip to main content

Single-particle cryo-EM structural analysis of Q-dependent transcription antitermination


EMSL Project ID
50733

Abstract

The transcription antitermination factor Q, produced by lambdoid bacteriophages, is a textbook example of a regulator of gene expression that functions at the level of transcription termination.

Q proteins function by binding to RNA polymerase-DNA-RNA transcription elongation complexes (TECs) and rendering TECs unable to recognize and respond to transcription termination signals.

Q proteins from different lambdoid bacteriophages comprise three different protein families (the Qlambda family, the Q21 family, and the Q82 family), with no detectable sequence similarity to each other and no detectable sequence similarity to other characterized proteins.

Q proteins from different protein families are thought to be analogs (with identical functions but unrelated structures) rather than homologs (with identical functions and related structures).

Q proteins have been the subject of extensive biochemical and genetic analysis spanning five decades. However, an understanding of the structural and mechanistic basis of transcription antitermination by Q proteins has remained elusive in the absence of three-dimensional structural information for Q-dependent antitermination complexes.

We propose to determine high-resolution single-particle-reconstruction cryo-EM structures of Qlambda-, Q21-, and Q82-dependent transcription antitermination complexes.

The availability of three-dimensional structures of Q-dependent transcription antitermination complexes will define the molecular interactions between Q proteins and RNA polymerase and between Q proteins and nucleic acids, and will define the mechanism of Q-dependent transcription antitermination.

The availability of three-dimensional structures of Q-dependent transcription antitermination complexes from all three protein families of lambdoid bacteriophage Q proteins will enable exploration of the remarkable ability of these structurally unrelated protein families to perform analogous biochemical functions.

Programmatic Access is requested (2 years; 9 days on Talos Arctica, preferably starting in the second- or third-quarter of 2019; 31 days on Titan Krios, preferably starting in the third- or fourth-quarter of 2019).

Project Details

Start Date
2019-04-15
End Date
2021-03-17
Status
Closed

Team

Principal Investigator

Richard Ebright
Institution
Rutgers University

Team Members

Vadim Molodtsov
Institution
Rutgers University

Zhou Yin
Institution
Waksman Institute of Microbiology, Rutgers University

Harry Scott
Institution
Oregon Health & Science University

Chengyuan Wang
Institution
Rutgers University

Irina El Khoury
Institution
Environmental Molecular Sciences Laboratory

Related Publications

Wang C., V. Molodtsov, E. Firlar, J.T. Kaelber, G. Blaha, M. Su, and R. Ebright. 2020. "Structural Basis of Transcription-translation Coupling." bioRxiv preprint 369, no. 6509:1359-1365. doi:10.1126/science.abb5317