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PDBsum entry 3eud
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Nuclear protein
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PDB id
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3eud
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References listed in PDB file
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Key reference
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Title
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Structure and functional studies of the cs domain of the essential h/aca ribonucleoparticle assembly protein shq1.
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Authors
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M.Singh,
F.A.Gonzales,
D.Cascio,
N.Heckmann,
G.Chanfreau,
J.Feigon.
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Ref.
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J Biol Chem, 2009,
284,
1906-1916.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
96%.
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Abstract
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H/ACA ribonucleoprotein particles are essential for ribosomal RNA and telomerase
RNA processing and metabolism. Shq1p has been identified as an essential
eukaryotic H/ACA small nucleolar (sno) ribonucleoparticle (snoRNP) biogenesis
and assembly factor. Shq1p is postulated to be involved in the early biogenesis
steps of H/ACA snoRNP complexes, and Shq1p depletion leads to a specific
decrease in H/ACA small nucleolar RNA levels and to defects in ribosomal RNA
processing. Shq1p contains two predicted domains as follows: an N-terminal CS
(named after CHORD-containing proteins and SGT1) or HSP20-like domain, and a
C-terminal region of high sequence homology called the Shq1 domain. Here we
report the crystal structure and functional studies of the Saccharomyces
cerevisiae Shq1p CS domain. The structure consists of a compact anti-parallel
beta-sandwich fold that is composed of two beta-sheets containing four and three
beta-strands, respectively, and a short alpha-helix. Deletion studies showed
that the CS domain is required for the essential functions of Shq1p. Point
mutations in residues Phe-6, Gln-10, and Lys-80 destabilize Shq1p in vivo and
induce a temperature-sensitive phenotype with depletion of H/ACA small nucleolar
RNAs and defects in rRNA processing. Although CS domains are frequently found in
co-chaperones of the Hsp90 molecular chaperone, no interaction was detected
between the Shq1p CS domain and yeast Hsp90 in vitro. These results show that
the CS domain is essential for Shq1p function in H/ACA snoRNP biogenesis in
vivo, possibly in an Hsp90-independent manner.
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Figure 2.
^1H-^15N HSQC spectra of the Shq1p CS domain. Overlay of
^1H-^15N HSQC spectra of Shq1p CS (red) and CS-L (cyan)
proteins. Assignments of amide resonances of CS are indicated
(K0 is a residue from the tag).
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Figure 8.
Comparison of Shq1p CS domain, Sgt1 CS domain, Sba1, and p23.
A, sequence alignment of Shq1p CS domain, Sgt1 CS domain, Sba1,
and p23. The boundaries of the constructs used for NMR or
crystallization studies are shown in parentheses. For Shq1p,
additional C-terminal residues beyond the end of Shq1p CS are
shown in gray for comparison with the other domains. The
residues of the Sba1 and p23 that are involved in binding with
Hsp90 are shown in blue and cyan box, respectively. B, ribbon
representations of the structures of Shq1p CS domain, Sgt1 CS
domain (Protein Data Bank code 1RL1), p23 (Protein Data Bank
code 1EJF), and Sba1 (Protein Data Bank code 2CG9). The
C-terminal α-helix found in Shq1p CS and the β-strand in the
equivalent region of p23 and Sba1 are shown in cyan. C, surface
representations of the CS domains showing the charge
distributions. The Shq1p CS domain does not have the extensive
basic surface in comparison with the Sgt1 CS domain, p23, and
Sba1.
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The above figures are
reprinted
from an Open Access publication published by the ASBMB:
J Biol Chem
(2009,
284,
1906-1916)
copyright 2009.
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