7XJG

Cryo-EM structure of E.coli retron-Ec86 in complex with its effector at 2.5 angstrom

Summary for 7XJG

• Entry DOI: 10.2210/pdb7xjg/pdb
• EMDB information: 31829 33226
• Descriptor: RNA-directed DNA polymerase from retron EC86, retron St85 family effector protein, DNA (105-MER), ... (6 entities in total)
• Functional Keywords: reverse transcriptase, rna binding protein, rna binding protein-dna-rna complex, rna binding protein/dna/rna
• Biological source: Escherichia coli; More
• Total number of polymer chains: 10
• Total formula weight: 272550.79

Authors

Wang, Y.J.,Guan, Z.Y.,Zou, T.T. (deposition date: 2022-04-17, release date: 2022-09-14, Last modification date: 2025-06-25)

Primary citation

Wang, Y.,Guan, Z.,Wang, C.,Nie, Y.,Chen, Y.,Qian, Z.,Cui, Y.,Xu, H.,Wang, Q.,Zhao, F.,Zhang, D.,Tao, P.,Sun, M.,Yin, P.,Jin, S.,Wu, S.,Zou, T.
Cryo-EM structures of Escherichia coli Ec86 retron complexes reveal architecture and defence mechanism.
Nat Microbiol, 7:1480-1489, 2022

PubMed Abstract: First discovered in the 1980s, retrons are bacterial genetic elements consisting of a reverse transcriptase and a non-coding RNA (ncRNA). Retrons mediate antiphage defence in bacteria but their structure and defence mechanisms are unknown. Here, we investigate the Escherichia coli Ec86 retron and use cryo-electron microscopy to determine the structures of the Ec86 (3.1 Å) and cognate effector-bound Ec86 (2.5 Å) complexes. The Ec86 reverse transcriptase exhibits a characteristic right-hand-like fold consisting of finger, palm and thumb subdomains. Ec86 reverse transcriptase reverse-transcribes part of the ncRNA into satellite, multicopy single-stranded DNA (msDNA, a DNA-RNA hybrid) that we show wraps around the reverse transcriptase electropositive surface. In msDNA, both inverted repeats are present and the 3' sides of the DNA/RNA chains are close to the reverse transcriptase active site. The Ec86 effector adopts a two-lobe fold and directly binds reverse transcriptase and msDNA. These findings offer insights into the structure-function relationship of the retron-effector unit and provide a structural basis for the optimization of retron-based genome editing systems.

PubMed: 35982312
DOI: 10.1038/s41564-022-01197-7

Experimental method

ELECTRON MICROSCOPY (2.51 Å)