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Structure and Conformational Dynamics of the Human Spliceosomal Bact Complex
David Haselbach1, Ilya Komarov2, Dmitry E Agafonov2
1Department for Structural Dynamics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Cell
|January 24, 2018
Summary
Researchers visualized the human Bact spliceosome, a molecular machine that removes introns from RNA. This structure reveals how the spliceosome, or RNA splicing complex, is poised for but blocked from its first catalytic step.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- The spliceosome is a large and dynamic molecular machine responsible for removing introns from pre-mRNA.
- Understanding the spliceosome's structure and dynamics is crucial for comprehending gene expression regulation.
Purpose of the Study:
- To determine the 3D structure of the human Bact spliceosome using cryo-electron microscopy (cryo-EM).
- To investigate the dynamic behavior and conformational states of the spliceosome.
Main Methods:
- Cryo-electron microscopy (cryo-EM) to obtain high-resolution 3D structure.
- Principal component analysis (PCA) to analyze dynamic behavior and conformational states.
Main Results:
- Reported the 3.4 Å resolution cryo-EM structure of the human Bact spliceosome.
- Identified eight major conformational states through energy landscape calculations and PCA.
- Observed similarities to yeast spliceosomes but highlighted differences, including the presence of RNA helicase Aquarius and peptidyl prolyl isomerases.
Conclusions:
- The Bact spliceosome is activated but functionally blocked before the first catalytic step.
- Conformational flexibility and dynamic interactions are key to spliceosome assembly and catalytic activation.
- The study provides insights into the intricate mechanisms governing RNA splicing.
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