Cryo-EM Structures of a Group II Intron Reverse Splicing into DNA
| Autor: | Cheng Zhang, Navtej Toor, Xiaodong Yan, Timothy S. Baker, Dmitry Lyumkis, Jason Hingey, Daniel B. Haack |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Protein Structure
Spliceosome Retroelements RNA Splicing retroelement Medical and Health Sciences Article General Biochemistry Genetics and Molecular Biology ribozyme splicing 03 medical and health sciences chemistry.chemical_compound group II intron 0302 clinical medicine Catalytic Domain Escherichia coli DNA Integration Nucleic acid structure RNA structure 030304 developmental biology 0303 health sciences biology Cryoelectron Microscopy Ribozyme RNA RNA-Directed DNA Polymerase Group II intron Biological Sciences Protein Structure Tertiary Cell biology chemistry RNA splicing Spliceosomes biology.protein cryo-EM Nucleic Acid Conformation maturase spliceosome Tertiary 030217 neurology & neurosurgery DNA Developmental Biology |
| Zdroj: | Cell Cell, vol 178, iss 3 |
| ISSN: | 0092-8674 |
| DOI: | 10.1016/j.cell.2019.06.035 |
| Popis: | Group II introns are a class of retroelements that invade DNA through a copy-and-paste mechanism known as retrotransposition. Their coordinated activities occur within a complex that includes a maturase protein, which promotes splicing through an unknown mechanism. The mechanism of splice site exchange within the RNA active site during catalysis also remains unclear. We determined two cryo-EM structures at 3.6 Å resolution of a group II intron reverse splicing into DNA. These structures reveal that the branch-site domain VI helix swings 90°, enabling substrate exchange during DNA integration. The maturase assists catalysis through a transient RNA-protein contact with domain VI that positions the branch-site adenosine for lariat formation during forward splicing. These findings provide the first direct evidence for the role the maturase plays during group II intron catalysis. The domain VI dynamics closely parallel spliceosomal branch-site helix movement and provide strong evidence for a retroelement origin of the spliceosome. |
| Databáze: | OpenAIRE |
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