+Open data
-Basic information
Entry | Database: EMDB / ID: EMD-30597 | |||||||||
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Title | Cryo-EM map of POT1 bound by TPP1 in extended conformation | |||||||||
Map data | Extended Conformation | |||||||||
Sample |
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Biological species | Homo sapiens (human) | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 9.6 Å | |||||||||
Authors | Smith EW / Liu ZB / Lattmann S / Ahsan B / Rhodes D | |||||||||
Funding support | Singapore, 1 items
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Citation | Journal: PLoS One / Year: 2022 Title: Insights into POT1 structural dynamics revealed by cryo-EM. Authors: Emmanuel W Smith / Simon Lattmann / Zhehui Barry Liu / Bilal Ahsan / Daniela Rhodes / Abstract: Telomeres are protein-DNA complexes that protect the ends of linear eukaryotic chromosomes. Mammalian telomeric DNA consists of 5'-(TTAGGG)n-3' double-stranded repeats, followed by up to several ...Telomeres are protein-DNA complexes that protect the ends of linear eukaryotic chromosomes. Mammalian telomeric DNA consists of 5'-(TTAGGG)n-3' double-stranded repeats, followed by up to several hundred bases of a 3' single-stranded G-rich overhang. The G-rich overhang is bound by the shelterin component POT1 which interacts with TPP1, the component involved in telomerase recruitment. A previously published crystal structure of the POT1 N-terminal half bound to the high affinity telomeric ligand 5'-TTAGGGTTAG-3' showed that the first six nucleotides, TTAGGG, are bound by the OB1 fold, while the adjacent OB2 binds the last four, TTAG. Here, we report two cryo-EM structures of full-length POT1 bound by the POT1-binding domain of TPP1. The structures differ in the relative orientation of the POT1 OB1 and OB2, suggesting that these two DNA-binding OB folds take up alternative conformations. Supporting DNA binding studies using telomeric ligands in which the OB1 and OB2 binding sites were spaced apart, show that POT1 binds with similar affinities to spaced or contiguous binding sites, suggesting plasticity in DNA binding and a role for the alternative conformations observed. A likely explanation is that the structural flexibility of POT1 enhances binding to the tandemly arranged telomeric repeats and hence increases telomere protection. | |||||||||
History |
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-Structure visualization
Movie |
Movie viewer |
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Structure viewer | EM map: SurfViewMolmilJmol/JSmol |
Supplemental images |
-Downloads & links
-EMDB archive
Map data | emd_30597.map.gz | 1.8 MB | EMDB map data format | |
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Header (meta data) | emd-30597-v30.xml emd-30597.xml | 7.7 KB 7.7 KB | Display Display | EMDB header |
Images | emd_30597.png | 26.3 KB | ||
Archive directory | http://ftp.pdbj.org/pub/emdb/structures/EMD-30597 ftp://ftp.pdbj.org/pub/emdb/structures/EMD-30597 | HTTPS FTP |
-Validation report
Summary document | emd_30597_validation.pdf.gz | 281.3 KB | Display | EMDB validaton report |
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Full document | emd_30597_full_validation.pdf.gz | 280.9 KB | Display | |
Data in XML | emd_30597_validation.xml.gz | 5.4 KB | Display | |
Data in CIF | emd_30597_validation.cif.gz | 6.1 KB | Display | |
Arichive directory | https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-30597 ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-30597 | HTTPS FTP |
-Related structure data
Related structure data | C: citing same article (ref.) |
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Similar structure data |
-Links
EMDB pages | EMDB (EBI/PDBe) / EMDataResource |
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-Map
File | Download / File: emd_30597.map.gz / Format: CCP4 / Size: 30.5 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Annotation | Extended Conformation | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.1 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
-Sample components
-Entire : Complex of POT1 with TPP1
Entire | Name: Complex of POT1 with TPP1 |
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Components |
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-Supramolecule #1: Complex of POT1 with TPP1
Supramolecule | Name: Complex of POT1 with TPP1 / type: complex / ID: 1 / Parent: 0 |
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Source (natural) | Organism: Homo sapiens (human) |
Recombinant expression | Organism: Baculovirus |
-Experimental details
-Structure determination
Method | cryo EM |
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Processing | single particle reconstruction |
Aggregation state | particle |
-Sample preparation
Buffer | pH: 7.8 |
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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 K2 SUMMIT (4k x 4k) / Average electron dose: 50.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | Model: Titan Krios / Image courtesy: FEI Company |
-Image processing
Final reconstruction | Resolution.type: BY AUTHOR / Resolution: 9.6 Å / Resolution method: FSC 0.143 CUT-OFF / Software - Name: RELION (ver. 3.0) / Number images used: 32488 |
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Initial angle assignment | Type: MAXIMUM LIKELIHOOD |
Final angle assignment | Type: MAXIMUM LIKELIHOOD |