Related Experiment Videos
Escherichia coli RNA polymerase core and holoenzyme structures
R D Finn1, E V Orlova, B Gowen
1Departments of Biochemistry and Biology, Imperial College of Science, Technology and Medicine, London SW7 2AY, UK.
The EMBO Journal
|December 16, 2000
Summary
Researchers visualized Escherichia coli RNA polymerase structures using cryo-electron microscopy. They revealed conformational changes between core RNA polymerase and the sigma(70) holoenzyme, aiding subunit localization.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Multisubunit RNA polymerase is crucial for gene expression regulation.
- Understanding RNA polymerase structure is key to deciphering gene regulation mechanisms.
Purpose of the Study:
- To determine the high-resolution structures of Escherichia coli core RNA polymerase and sigma(70) holoenzyme.
- To elucidate the conformational differences between core and holoenzyme forms.
Main Methods:
- Cryo-electron microscopy (cryo-EM) was employed to obtain structures.
- Angular reconstitution techniques were used for image processing and structure determination.
Main Results:
- An 11.0 Å structure of the core RNA polymerase and a 9.5 Å structure of the sigma(70) holoenzyme were determined.
- Core RNA polymerase was observed in an open conformation.
- Significant conformational changes were identified between core and holoenzyme, primarily involving the ss' subunit.
Conclusions:
- The study provides detailed structural insights into RNA polymerase.
- Localization of all common subunits (alpha(2), ss, ss') was achieved in both structures.
- The findings suggest the position of the sigma(70) subunit within the holoenzyme structure.