6W6W image
Entry Detail
PDB ID:
6W6W
EMDB ID:
Title:
Cryo-EM structure of CST bound to telomeric single-stranded DNA
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2020-03-17
Release Date:
2020-06-03
Method Details:
Experimental Method:
Resolution:
3.00 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:CST complex subunit CTC1
Chain IDs:A, C (auth: B)
Chain Length:1233
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:CST complex subunit STN1
Chain IDs:D (auth: C)
Chain Length:374
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:CST complex subunit TEN1
Chain IDs:E (auth: D)
Chain Length:152
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(P*TP*AP*GP*G)-3')
Chain IDs:B (auth: E)
Chain Length:4
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
The structure of human CST reveals a decameric assembly bound to telomeric DNA.
Science 368 1081 1085 (2020)
PMID: 32499435 DOI: 10.1126/science.aaz9649

Abstact

The CTC1-STN1-TEN1 (CST) complex is essential for telomere maintenance and resolution of stalled replication forks genome-wide. Here, we report the 3.0-angstrom cryo-electron microscopy structure of human CST bound to telomeric single-stranded DNA (ssDNA), which assembles as a decameric supercomplex. The atomic model of the 134-kilodalton CTC1 subunit, built almost entirely de novo, reveals the overall architecture of CST and the DNA-binding anchor site. The carboxyl-terminal domain of STN1 interacts with CTC1 at two separate docking sites, allowing allosteric mediation of CST decamer assembly. Furthermore, ssDNA appears to staple two monomers to nucleate decamer assembly. CTC1 has stronger structural similarity to Replication Protein A than the expected similarity to yeast Cdc13. The decameric structure suggests that CST can organize ssDNA analogously to the nucleosome's organization of double-stranded DNA.

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Primary Citation of related structures