4JQF: Structure Of The C-terminal Domain Of Human Telomeric Stn1

The identification of the human homologue of the yeast CST in 2009 posed a new challenge in our understanding of the mechanism of telomere capping in higher eukaryotes. The high-resolution structure of the human Stn1-Ten1 (hStn1-Ten1) complex presented here reveals that hStn1 consists of an OB domain and tandem C-terminal wHTH motifs, while hTen1 consists of a single OB fold. Contacts between the OB domains facilitate formation of a complex that is strikingly similar to the replication protein A (RPA) and yeast Stn1-Ten1 (Ten1) complexes. The hStn1-Ten1 complex exhibits non-specific single-stranded DNA activity that is primarily dependent on hStn1. Cells expressing hStn1 mutants defective for dimerization with hTen1 display elongated telomeres and telomere defects associated with telomere uncapping, suggesting that the telomeric function of hCST is hTen1 dependent. Taken together the data presented here show that the structure of the hStn1-Ten1 subcomplex is conserved across species. Cell based assays indicate that hTen1 is critical for the telomeric function of hCST, both in telomere protection and downregulation of telomerase function.
PDB ID: 4JQFDownload
MMDB ID: 110733
PDB Deposition Date: 2013/3/20
Updated in MMDB: 2013/08
Experimental Method:
x-ray diffraction
Resolution: 1.6  Å
Source Organism:
Similar Structures:
Biological Unit for 4JQF: monomeric; determined by author and by software (PISA)
Molecular Components in 4JQF
Label Count Molecule
Protein (1 molecule)
CST Complex Subunit Stn1(Gene symbol: STN1)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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