6ME0 image
Entry Detail
PDB ID:
6ME0
EMDB ID:
Title:
Structure of a group II intron retroelement prior to DNA integration
Biological Source:
PDB Version:
Deposition Date:
2018-09-05
Release Date:
2019-08-14
Method Details:
Experimental Method:
Resolution:
3.60 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polyribonucleotide
Description:T.el4h RNA
Chain IDs:A
Chain Length:866
Number of Molecules:1
Biological Source:Thermosynechococcus elongatus
Polymer Type:polydeoxyribonucleotide
Description:Sense Target DNA
Chain IDs:B
Chain Length:45
Number of Molecules:1
Biological Source:Thermosynechococcus elongatus
Polymer Type:polypeptide(L)
Description:Maturase reverse transcriptase
Chain IDs:C
Chain Length:562
Number of Molecules:1
Biological Source:Thermosynechococcus elongatus (strain BP-1)
Primary Citation
Cryo-EM Structures of a Group II Intron Reverse Splicing into DNA.
Cell 178 612 623.e12 (2019)
PMID: 31348888 DOI: 10.1016/j.cell.2019.06.035

Abstact

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.

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Primary Citation of related structures