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PDBsum entry 2z5e
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References listed in PDB file
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Key reference
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Title
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Crystal structure of a chaperone complex that contributes to the assembly of yeast 20s proteasomes.
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Authors
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H.Yashiroda,
T.Mizushima,
K.Okamoto,
T.Kameyama,
H.Hayashi,
T.Kishimoto,
S.Niwa,
M.Kasahara,
E.Kurimoto,
E.Sakata,
K.Takagi,
A.Suzuki,
Y.Hirano,
S.Murata,
K.Kato,
T.Yamane,
K.Tanaka.
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Ref.
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Nat Struct Mol Biol, 2008,
15,
228-236.
[DOI no: ]
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PubMed id
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Abstract
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Eukaryotic 20S proteasomes are composed of two alpha-rings and two beta-rings,
which form an alphabetabetaalpha stacked structure. Here we describe a
proteasome-specific chaperone complex, designated Dmp1-Dmp2, in budding yeast.
Dmp1-Dmp2 directly bound to the alpha5 subunit to facilitate alpha-ring
formation. In Deltadmp1 cells, alpha-rings lacking alpha4 and decreased
formation of 20S proteasomes were observed. Dmp1-Dmp2 interacted with proteasome
precursors early during proteasome assembly and dissociated from the precursors
before the formation of half-proteasomes. Notably, the crystallographic
structures of Dmp1 and Dmp2 closely resemble that of PAC3-a mammalian
proteasome-assembling chaperone; nonetheless, neither Dmp1 nor Dmp2 showed
obvious sequence similarity to PAC3. The structure of the Dmp1-Dmp2-alpha5
complex reveals how this chaperone functions in proteasome assembly and why it
dissociates from proteasome precursors before the beta-rings are assembled.
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Figure 6.
(a) Above, a stereo ribbon diagram of the Dmp1–Dmp2  loop-
 5
complex. Dmp1, Dmp2 loop
and 5
are colored blue, red and cyan, respectively. Below, a ribbon
diagram of the 5
(PDB ID code: 1RYP; chain E, cyan) and  5
(PDB ID code: 1RYP; chain L, green) complex. The secondary
structural elements are labeled. (b) Close-up view of the
Dmp1–Dmp2 loop–
5
interface showing amino acids of Dmp1 (blue), Dmp2 (red) and
5
(cyan). Hydrogen bonds are indicated by dotted lines. (c)
Binding positions of the Dmp1–Dmp2 complex in the 20S
proteasome. Dmp1, Dmp2 and 5
are shown as ribbon representations and are colored blue, red
and cyan, respectively. C traces
are colored yellow in the -ring
and green in the [36]beta -ring. (d) Model of the Dmp1–Dmp2–
[37]alpha -ring complex derived from the published structure of
the yeast proteasome (PDB ID code: 1RYP).
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Figure 7.
(a) Structure of PAC3. A ribbon diagram of the PAC3
homodimer. Molecule A and molecule B are colored dark cyan and
olive, respectively. The secondary structural elements of PAC3
are labeled. (b) The structure of PAC3 (olive) is compared with
the structures of Dmp1 (blue) and Dmp2 (red). The secondary
structural elements are labeled. (c) Topology diagram of PAC3.
-Helices
and -strands
are represented by cylinders and arrows, respectively.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
Nat Struct Mol Biol
(2008,
15,
228-236)
copyright 2008.
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