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Open data
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Basic information
| Entry | ![]() | |||||||||
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| Title | Cte-A695U-branching,Mg,active | |||||||||
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Sample |
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Keywords | Cte-branching / back-splicing / cryo-EM / cirular RNA / SPLICING / RNA | |||||||||
| Biological species | Comamonas testosteroni KF-1 (bacteria) | |||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 3.04 Å | |||||||||
Authors | Ling XB / Ma JB | |||||||||
| Funding support | China, 1 items
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Citation | Journal: Nat Struct Mol Biol / Year: 2025Title: Structures of a natural circularly permuted group II intron reveal mechanisms of branching and backsplicing. Authors: Xiaobin Ling / Yuqi Yao / Jinbiao Ma / ![]() Abstract: Circularly permuted (CP) group II introns, identified in various bacteria phyla, swap domains D5 and D6 near the 5' end and have reversed splice sites (SSs), leading to backsplicing and circular RNA ...Circularly permuted (CP) group II introns, identified in various bacteria phyla, swap domains D5 and D6 near the 5' end and have reversed splice sites (SSs), leading to backsplicing and circular RNA formation. In this study, we present multiple high-resolution cryo-electron microscopy structures of a natural CP group II intron from Comamonas testosteroni KF-1 (Cte 1), elucidating the molecular mechanisms of branching and backsplicing. During branching, the 5' SS is positioned by an auxiliary sequence (AUX)-enhanced interaction between the exon-binding site and intron-binding site (IBS) and stacks on the branch-site adenosine within D6, allowing the attacking 2'-OH group to coordinate with a metal ion in the active center. In backsplicing, the 3' SS is aligned with the branching step, leaving IBS in the active center, stabilized by base pairing with the AUX, which enables the free 3'-end hydroxyl group to directly attack the scissile phosphate of 3' SS. Furthermore, a groove in Cte 1 may stabilize the circular RNA. These findings highlight a conserved catalytic mechanism for canonical group II introns, albeit facilitated by the versatile AUX, opening avenues for designing potent ribozymes producing circular RNAs. | |||||||||
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Structure visualization
| Supplemental images |
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Downloads & links
-EMDB archive
| Map data | emd_38182.map.gz | 111.2 MB | EMDB map data format | |
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| Header (meta data) | emd-38182-v30.xml emd-38182.xml | 15.5 KB 15.5 KB | Display Display | EMDB header |
| FSC (resolution estimation) | emd_38182_fsc.xml | 10.6 KB | Display | FSC data file |
| Images | emd_38182.png | 45.2 KB | ||
| Filedesc metadata | emd-38182.cif.gz | 5.2 KB | ||
| Others | emd_38182_half_map_1.map.gz emd_38182_half_map_2.map.gz | 116.1 MB 116.1 MB | ||
| Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-38182 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-38182 | HTTPS FTP |
-Validation report
| Summary document | emd_38182_validation.pdf.gz | 778 KB | Display | EMDB validaton report |
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| Full document | emd_38182_full_validation.pdf.gz | 777.6 KB | Display | |
| Data in XML | emd_38182_validation.xml.gz | 19.1 KB | Display | |
| Data in CIF | emd_38182_validation.cif.gz | 24.4 KB | Display | |
| Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-38182 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-38182 | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 8x9qMC ![]() 8x9kC ![]() 8x9lC ![]() 8x9mC ![]() 8x9nC ![]() 8x9oC M: atomic model generated by this map C: citing same article ( |
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Links
| EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Map
| File | Download / File: emd_38182.map.gz / Format: CCP4 / Size: 125 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
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| Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
| Voxel size | X=Y=Z: 0.832 Å | ||||||||||||||||||||||||||||||||||||
| Density |
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| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML:
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-Supplemental data
-Half map: #2
| File | emd_38182_half_map_1.map | ||||||||||||
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| Density Histograms |
-Half map: #1
| File | emd_38182_half_map_2.map | ||||||||||||
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| Density Histograms |
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Sample components
-Entire : Cte_branching_Mg_active
| Entire | Name: Cte_branching_Mg_active |
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| Components |
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-Supramolecule #1: Cte_branching_Mg_active
| Supramolecule | Name: Cte_branching_Mg_active / type: organelle_or_cellular_component / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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| Source (natural) | Organism: Comamonas testosteroni KF-1 (bacteria) |
-Macromolecule #1: RNA (809-MER)
| Macromolecule | Name: RNA (809-MER) / type: rna / ID: 1 / Number of copies: 1 |
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| Source (natural) | Organism: Comamonas testosteroni KF-1 (bacteria) |
| Molecular weight | Theoretical: 262.672312 KDa |
| Sequence | String: GCCGGGGCGC CACCCCGGAA GUGAUGCGAG UCGCCAACUC GCAUCACAAG CAAACGCUGU AGCCGCGUGC CUCUAAUAGG GCUGGCGCG GUUGCGAAGG GCGCUGGUGA GUGCAACUCU CACCUUCGAC CCAAUCCAUC UUGCGGCUCA ACCCCGCAAG A UCAUCGCC ...String: GCCGGGGCGC CACCCCGGAA GUGAUGCGAG UCGCCAACUC GCAUCACAAG CAAACGCUGU AGCCGCGUGC CUCUAAUAGG GCUGGCGCG GUUGCGAAGG GCGCUGGUGA GUGCAACUCU CACCUUCGAC CCAAUCCAUC UUGCGGCUCA ACCCCGCAAG A UCAUCGCC AGACCGCUGG CGGCGUACUG AGUGACAAAC GAGGCAAAAC CAAAUUGAAG UUGGGCGACC GUGAAACGGC GC UGGGCAG GAAAUGGCCC AGUGACCUGG UCAAUGGUGA AAGUCGGUGA AAGACCGACC GGUGGGGCGU AUCGAAAGAG CGC AACACC UGCCGCACAG GAUGGCUUCU GAGGUACCGG UGACGGUACA GAACGCGGAG GGGAAACCUG GAAGCGAGGG CACC UCGGG AAACCGGGGG UCGAUGCAUA GCUCAAACCU GUAACGGCAC CAGUGGAGGG UGCUGUGCGG AGCAACGUGG AGCCA CAGG CAUGAAGCCG UGGUUCGUAG UCGAUGAGAC AAGCGGUGAG UAAGGGAAGG GCUGCGAACA UCGCCUCCCC GAAAUC CAA GGAAAGCCGA AAGGCUAGCC GCUUUGUUGA GACAGUGGCG CCACGUUGCG CAUUAGCCGU GACCUAAACG GGGAACC UC UUGGCCGUAC CGACUCGGGU GGCACCGGUC GGGCUCGAUG GCUCAAGAGG GGGAGAUGUG AUGAUUAGGG UUUGACCC G UGAUGCGAUA CGACCGAAGC AUCCGGGGAG CUGUCUGACG AAGAGUCGGC AGCAGUGGGU UUGGCGACCC GCUCCGAAA GUCGCAAGC GENBANK: GENBANK: CP140157.1 |
-Macromolecule #2: MAGNESIUM ION
| Macromolecule | Name: MAGNESIUM ION / type: ligand / ID: 2 / Number of copies: 13 / Formula: MG |
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| Molecular weight | Theoretical: 24.305 Da |
-Macromolecule #3: POTASSIUM ION
| Macromolecule | Name: POTASSIUM ION / type: ligand / ID: 3 / Number of copies: 16 / Formula: K |
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| Molecular weight | Theoretical: 39.098 Da |
-Macromolecule #4: water
| Macromolecule | Name: water / type: ligand / ID: 4 / Number of copies: 10 / Formula: HOH |
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| Molecular weight | Theoretical: 18.015 Da |
| Chemical component information | ![]() ChemComp-HOH: |
-Experimental details
-Structure determination
| Method | cryo EM |
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Processing | single particle reconstruction |
| Aggregation state | particle |
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Sample preparation
| Buffer | pH: 7.5 |
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| Vitrification | Cryogen name: ETHANE |
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Electron microscopy
| Microscope | TFS KRIOS |
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| Image recording | Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Average electron dose: 52.0 e/Å2 |
| Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
| Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.2 µm / Nominal defocus min: 1.2 µm |
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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About Yorodumi




Keywords
Comamonas testosteroni KF-1 (bacteria)
Authors
China, 1 items
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Processing
FIELD EMISSION GUN

