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Open data
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Basic information
Entry | ![]() | |||||||||
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Title | Cte-Branch Product, Mg, post | |||||||||
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![]() | CP group ii intron / Cte / back-splicing / circular RNA / cryo-EM / SPLICING / RNA | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 2.78 Å | |||||||||
![]() | Ling XB / Ma JB | |||||||||
Funding support | ![]()
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![]() | ![]() Title: 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. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 54.6 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 14.3 KB 14.3 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 8.4 KB | Display | ![]() |
Images | ![]() | 56 KB | ||
Filedesc metadata | ![]() | 5.1 KB | ||
Others | ![]() ![]() | 59.5 MB 59.5 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8x9mMC ![]() 8x9kC ![]() 8x9lC ![]() 8x9nC ![]() 8x9oC ![]() 8x9qC M: atomic model generated by this map C: citing same article ( |
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Links
EMDB pages | ![]() ![]() |
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Map
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Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.064 Å | ||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: #1
File | emd_38175_half_map_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: #2
File | emd_38175_half_map_2.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
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Sample components
-Entire : Cte-Branch Product
Entire | Name: Cte-Branch Product |
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Components |
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-Supramolecule #1: Cte-Branch Product
Supramolecule | Name: Cte-Branch Product / type: organelle_or_cellular_component / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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Source (natural) | Organism: ![]() |
-Macromolecule #1: RNA (808-MER)
Macromolecule | Name: RNA (808-MER) / type: rna / ID: 1 / Number of copies: 1 |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 262.367094 KDa |
Sequence | String: GCCGGGGCGC CACCCCGGAA GUGAUGCGAG UCGCAACUCG CAUCACAAGC AAACGCUGUA GCCGCGUGCC UCUAAUAGGG CUGGCGCGG UUGCGAAGGG CGCUGGUGAG UGCAACUCUC ACCUUCGACC CAAUCCAUCU UGCGGCUCAA CCCCGCAAGA U CAUCGCCA ...String: GCCGGGGCGC CACCCCGGAA GUGAUGCGAG UCGCAACUCG CAUCACAAGC AAACGCUGUA GCCGCGUGCC UCUAAUAGGG CUGGCGCGG UUGCGAAGGG CGCUGGUGAG UGCAACUCUC ACCUUCGACC CAAUCCAUCU UGCGGCUCAA CCCCGCAAGA U CAUCGCCA GACCGCUGGC GGCGUACUGA GUGACAAACG AGGCAAAACC AAAUUGAAGU UGGGCGACCG UGAAACGGCG CU GGGCAGG AAAUGGCCCA GUGACCUGGU CAAUGGUGAA AGUCGGUGAA AGACCGACCG GUGGGGCGUA UCGAAAGAGC GCA ACACCU GCCGCACAGG AUGGCUUCUG AGGUACCGGU GACGGUACAG AACGCGGAGG GGAAACCUGG AAGCGAGGGC ACCU CGGGA AACCGGGGGU CGAUGCAUAG CUCAAACCUG UAACGGCACC AGUGGAGGGU GCUGUGCGGA GCAACGUGGA GCCAC AGGC AUGAAGCCGU GGUUCGUAGU CGAUGAGACA AGCGGUGAGU AAGGGAAGGG CUGCGAACAU CGCCUCCCCG AAAUCC AAG GAAAGCCGAA AGGCUAGCCG CUUUGUUGAG ACAGUGGCGC CACGUUGCGC AUUAGCCGUG ACCUAAACGG GGAACCU CU UGGCCGUACC GACUCGGGUG GCACCGGUCG GGCUCGAUGG CUCAAGAGGG GGAGAUGUGA UGAUUAGGGU UUGACCCG U GAUGCGAUAC GACCGAAGCA UCCGGGGAGC UGUCUGACGA AGAGUCGGCA GCAGUGGGUU UGGCGACCCG CUCCGAAAG UCGCAAGC |
-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: 13 / 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: 5 / 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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![]() | 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: ![]() |
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 |