 |
PDBsum entry 3kf8
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Structural protein
|
PDB id
|
|
|
|
3kf8
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
208 a.a.
|
|
|
|
|
|
|
|
|
|
|
121 a.a.
|
|
|
|
|
|
|
|
|
|
|
193 a.a.
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Stn1-Ten1 is an rpa2-Rpa3-Like complex at telomeres.
|
|
|
Authors
|
|
J.Sun,
E.Y.Yu,
Y.Yang,
L.A.Confer,
S.H.Sun,
K.Wan,
N.F.Lue,
M.Lei.
|
|
|
Ref.
|
|
Genes Dev, 2009,
23,
2900-2914.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
In budding yeast, Cdc13, Stn1, and Ten1 form a heterotrimeric complex (CST) that
is essential for telomere protection and maintenance. Previous bioinformatics
analysis revealed a putative oligonucleotide/oligosaccharide-binding (OB) fold
at the N terminus of Stn1 (Stn1N) that shows limited sequence similarity to the
OB fold of Rpa2, a subunit of the eukaryotic ssDNA-binding protein complex
replication protein A (RPA). Here we present functional and structural analyses
of Stn1 and Ten1 from multiple budding and fission yeast. The crystal structure
of the Candida tropicalis Stn1N complexed with Ten1 demonstrates an
Rpa2N-Rpa3-like complex. In both structures, the OB folds of the two components
pack against each other through interactions between two C-terminal helices. The
structure of the C-terminal domain of Saccharomyces cerevisiae Stn1 (Stn1C) was
found to comprise two related winged helix-turn-helix (WH) motifs, one of which
is most similar to the WH motif at the C terminus of Rpa2, again supporting the
notion that Stn1 resembles Rpa2. The crystal structure of the fission yeast
Schizosaccharomyces pombe Stn1N-Ten1 complex exhibits a virtually identical
architecture as the C. tropicalis Stn1N-Ten1. Functional analyses of the Candida
albicans Stn1 and Ten1 proteins revealed critical roles for these proteins in
suppressing aberrant telomerase and recombination activities at telomeres.
Mutations that disrupt the Stn1-Ten1 interaction induce telomere uncapping and
abolish the telomere localization of Ten1. Collectively, our structural and
functional studies illustrate that, instead of being confined to budding yeast
telomeres, the CST complex may represent an evolutionarily conserved RPA-like
telomeric complex at the 3' overhangs that works in parallel with or instead of
the well-characterized POT1-TPP1/TEBPalpha-beta complex.
|
|
|
|
|
|
|
