+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-26866 | ||||||||||||
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Title | Tetrahymena CST with Polymerase alpha-Primase | ||||||||||||
Map data | full map | ||||||||||||
Sample |
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Keywords | telomerase / RNP / CST / polymerase / REPLICATION | ||||||||||||
Function / homology | Function and homology information alpha DNA polymerase:primase complex / lagging strand elongation / mitotic DNA replication initiation / telomerase holoenzyme complex / leading strand elongation / DNA replication origin binding / telomere maintenance via telomerase / single-stranded DNA binding / chromosome, telomeric region / DNA-directed DNA polymerase ...alpha DNA polymerase:primase complex / lagging strand elongation / mitotic DNA replication initiation / telomerase holoenzyme complex / leading strand elongation / DNA replication origin binding / telomere maintenance via telomerase / single-stranded DNA binding / chromosome, telomeric region / DNA-directed DNA polymerase / DNA-directed DNA polymerase activity / nucleotide binding / chromatin binding / metal ion binding Similarity search - Function | ||||||||||||
Biological species | Tetrahymena thermophila (eukaryote) | ||||||||||||
Method | single particle reconstruction / cryo EM / Resolution: 4.2 Å | ||||||||||||
Authors | He Y / Song H / Chan H / Wang Y / Liu B / Susac L / Zhou ZH / Feigon J | ||||||||||||
Funding support | United States, 3 items
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Citation | Journal: Nature / Year: 2022 Title: Structure of Tetrahymena telomerase-bound CST with polymerase α-primase. Authors: Yao He / He Song / Henry Chan / Baocheng Liu / Yaqiang Wang / Lukas Sušac / Z Hong Zhou / Juli Feigon / Abstract: Telomeres are the physical ends of linear chromosomes. They are composed of short repeating sequences (such as TTGGGG in the G-strand for Tetrahymena thermophila) of double-stranded DNA with a single- ...Telomeres are the physical ends of linear chromosomes. They are composed of short repeating sequences (such as TTGGGG in the G-strand for Tetrahymena thermophila) of double-stranded DNA with a single-strand 3' overhang of the G-strand and, in humans, the six shelterin proteins: TPP1, POT1, TRF1, TRF2, RAP1 and TIN2. TPP1 and POT1 associate with the 3' overhang, with POT1 binding the G-strand and TPP1 (in complex with TIN2) recruiting telomerase via interaction with telomerase reverse transcriptase (TERT). The telomere DNA ends are replicated and maintained by telomerase, for the G-strand, and subsequently DNA polymerase α-primase (PolαPrim), for the C-strand. PolαPrim activity is stimulated by the heterotrimeric complex CTC1-STN1-TEN1 (CST), but the structural basis of the recruitment of PolαPrim and CST to telomere ends remains unknown. Here we report cryo-electron microscopy (cryo-EM) structures of Tetrahymena CST in the context of the telomerase holoenzyme, in both the absence and the presence of PolαPrim, and of PolαPrim alone. Tetrahymena Ctc1 binds telomerase subunit p50, a TPP1 orthologue, on a flexible Ctc1 binding motif revealed by cryo-EM and NMR spectroscopy. The PolαPrim polymerase subunit POLA1 binds Ctc1 and Stn1, and its interface with Ctc1 forms an entry port for G-strand DNA to the POLA1 active site. We thus provide a snapshot of four key components that are required for telomeric DNA synthesis in a single active complex-telomerase-core ribonucleoprotein, p50, CST and PolαPrim-that provides insights into the recruitment of CST and PolαPrim and the handoff between G-strand and C-strand synthesis. | ||||||||||||
History |
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-Structure visualization
Supplemental images |
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-Downloads & links
-EMDB archive
Map data | emd_26866.map.gz | 227.5 MB | EMDB map data format | |
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Header (meta data) | emd-26866-v30.xml emd-26866.xml | 24.6 KB 24.6 KB | Display Display | EMDB header |
FSC (resolution estimation) | emd_26866_fsc.xml | 14.2 KB | Display | FSC data file |
Images | emd_26866.png | 59.9 KB | ||
Masks | emd_26866_msk_1.map | 244.1 MB | Mask map | |
Filedesc metadata | emd-26866.cif.gz | 7.8 KB | ||
Others | emd_26866_half_map_1.map.gz emd_26866_half_map_2.map.gz | 193.7 MB 193.7 MB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-26866 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-26866 | HTTPS FTP |
-Related structure data
Related structure data | 7uy7MC 7uy5C 7uy6C 7uy8C C: citing same article (ref.) M: atomic model generated by this map |
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Similar structure data | Similarity search - Function & homologyF&H Search |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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Related items in Molecule of the Month |
-Map
File | Download / File: emd_26866.map.gz / Format: CCP4 / Size: 244.1 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||
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Annotation | full map | ||||||||||||||||||||
Voxel size | X=Y=Z: 1.1 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Mask #1
File | emd_26866_msk_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: half1
File | emd_26866_half_map_1.map | ||||||||||||
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Annotation | half1 | ||||||||||||
Projections & Slices |
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Density Histograms |
-Half map: half2
File | emd_26866_half_map_2.map | ||||||||||||
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Annotation | half2 | ||||||||||||
Projections & Slices |
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Density Histograms |
-Sample components
+Entire : Tetrahymena CST-PolaPrim
+Supramolecule #1: Tetrahymena CST-PolaPrim
+Supramolecule #2: Tetrahymena CST
+Supramolecule #3: Tetrahymena DNA polymerase alpha-primase
+Macromolecule #1: Telomerase-associated protein of 75 kDa
+Macromolecule #2: Telomerase-associated protein of 45 kDa
+Macromolecule #3: Telomerase-associated protein of 19 kDa
+Macromolecule #4: Telomerase associated protein p50
+Macromolecule #5: DNA polymerase
+Macromolecule #6: Telomere DNA
+Macromolecule #7: ZINC ION
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Buffer | pH: 8 |
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Vitrification | Cryogen name: ETHANE |
-Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Average electron dose: 55.0 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: 4.0 µm / Nominal defocus min: 0.8 µm |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |