7UIN

CryoEM Structure of an Group II Intron Retroelement

Summary for 7UIN

• Entry DOI: 10.2210/pdb7uin/pdb
• EMDB information: 26550
• Descriptor: E.r IIC Intron, Group II intron reverse transcriptase/maturase, DNA (37-MER), ... (6 entities in total)
• Functional Keywords: rna, intron, group ii, maturase, splicing, retrotransposition, rna binding protein-rna-dna complex, rna binding protein/rna/dna
• Biological source: [Eubacterium] rectale; More
• Total number of polymer chains: 3
• Total formula weight: 267983.70

Authors

Chung, K.,Xu, L. (deposition date: 2022-03-29, release date: 2022-11-23, Last modification date: 2024-06-12)

Primary citation

Chung, K.,Xu, L.,Chai, P.,Peng, J.,Devarkar, S.C.,Pyle, A.M.
Structures of a mobile intron retroelement poised to attack its structured DNA target
Science, 378:627-634, 2022

PubMed Abstract: Group II introns are ribozymes that catalyze their self-excision and function as retroelements that invade DNA. As retrotransposons, group II introns form ribonucleoprotein (RNP) complexes that roam the genome, integrating by reversal of forward splicing. Here we show that retrotransposition is achieved by a tertiary complex between a structurally elaborate ribozyme, its protein mobility factor, and a structured DNA substrate. We solved cryo-electron microscopy structures of an intact group IIC intron-maturase retroelement that was poised for integration into a DNA stem-loop motif. By visualizing the RNP before and after DNA targeting, we show that it is primed for attack and fits perfectly with its DNA target. This study reveals design principles of a prototypical retroelement and reinforces the hypothesis that group II introns are ancient elements of genetic diversification.

PubMed: 36356138
DOI: 10.1126/science.abq2844

Experimental method

ELECTRON MICROSCOPY (2.8 Å)