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Promoter Capture Hi-C: High-resolution, Genome-wide Profiling of Promoter Interactions
Published on: June 28, 2018
Structural insights into the activity of enhancer-binding proteins
Mathieu Rappas1, Jorg Schumacher, Fabienne Beuron
1Department of Biological Sciences, Imperial College London, London, SW7 2AZ, UK.
Science (New York, N.Y.)
|March 26, 2005
Summary
Activators of sigma54-RNA polymerase use ATP hydrolysis to activate transcription. This study reveals how PspF(1-275) binds sigma54 via nucleotide-dependent conformational changes, identified using cryo-EM.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Sigma54-RNA polymerase holoenzyme controls bacterial transcription initiation.
- Activator proteins are essential for sigma54-dependent transcription, utilizing ATP hydrolysis.
- Phage shock protein F [PspF(1-275)] is a key sigma54 activator.
Purpose of the Study:
- To elucidate the structural mechanism of PspF(1-275) interaction with sigma54.
- To understand the role of ATP hydrolysis in activator-sigma54 complex formation.
- To determine the structure of the activator-sigma54 complex at near-atomic resolution.
Main Methods:
- Cryogenic electron microscopy (cryo-EM) to determine the structure of PspF(1-275) bound to sigma54.
- Fitting of a high-resolution crystal structure of PspF(1-275) into the cryo-EM map.
- Mutational analysis and comparison of enhancer-binding domains in different nucleotide states.
Main Results:
- A 20 angstrom resolution cryo-EM structure of the PspF(1-275)-sigma54 complex was obtained.
- Two specific loops within PspF(1-275) were identified as crucial for sigma54 binding.
- Nucleotide-dependent conformational changes in PspF(1-275) were proposed to facilitate sigma54 association.
Conclusions:
- The study provides a structural basis for understanding sigma54 activator function.
- Conformational flexibility driven by ATP binding and hydrolysis is critical for activator-sigma54 interaction.
- This work advances knowledge of bacterial transcription regulation mechanisms.
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