Back to Search
Start Over
Cryo-EM Structures of a Group II Intron Reverse Splicing into DNA.
- Source :
-
Cell [Cell] 2019 Jul 25; Vol. 178 (3), pp. 612-623.e12. - Publication Year :
- 2019
-
Abstract
- 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 of 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.<br /> (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Subjects :
- Catalytic Domain
Cryoelectron Microscopy
Escherichia coli genetics
Escherichia coli metabolism
Nucleic Acid Conformation
Protein Structure, Tertiary
RNA metabolism
RNA-Directed DNA Polymerase metabolism
Retroelements
Spliceosomes chemistry
RNA chemistry
RNA Splicing
RNA-Directed DNA Polymerase chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1097-4172
- Volume :
- 178
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Cell
- Publication Type :
- Academic Journal
- Accession number :
- 31348888
- Full Text :
- https://doi.org/10.1016/j.cell.2019.06.035