 |
PDBsum entry 1j2q
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
(+ 1 more)
237 a.a.
|
|
|
|
|
|
|
|
|
|
|
(+ 1 more)
202 a.a.
|
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Investigations on the maturation and regulation of archaebacterial proteasomes.
|
|
|
Authors
|
|
M.Groll,
H.Brandstetter,
H.Bartunik,
G.Bourenkow,
R.Huber.
|
|
|
Ref.
|
|
J Mol Biol, 2003,
327,
75-83.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The 20S proteasome (core particle, CP) is a multifunctional protease complex and
composed of four heptameric subunit rings arranged in a hollow, barrel-shaped
structure. Here, we report the crystal structure of the CP from Archaeoglobus
fulgidus at 2.25A resolution. The analysis of the structure of early and late
assembly intermediates of this CP gives new insights in the maturation of
archaebacterial CPs and indicates similarities to assembly intermediates
observed in eukaryotes. We also show a striking difference in mechanism and
regulation of substrate access between eukaryotic and archaebacterial 20S
proteasomes. While eukaryotic CPs are auto-inhibited by the N-terminal tails of
the outer alpha-ring by imposing topological closure with a characteristic
sequence motif (YDR-motif) and show regulatory gating this segment is disordered
in the CP and differently structured in the alpha(7)-sub-complex of A.fulgidus
leaving a pore leading into the particle with a diameter of 13A. Mutagenesis and
functional studies indicate the absence of regulatory gating in the archaeal 20S
proteasome.
|
|
|
|
|
|
|
|
Figure 3.
Figure 3. Stereo view of the overlay of the C^a tracings of
the a-subunit from the a-ring (yellow) and the a-subunit from
the CP (blue).
|
|
Figure 5.
Figure 5. (a) and (b) Ribbon drawing of the a-ring from A.
fulgidus in top and side view, respectively. The N-terminal
segments are shown in red and the remaining part is shown in
blue. (c) Stereo drawing of the open channel with a 7-fold
averaged 2F[O] -F[C] map showing the YDR element. Contacts among
residues of the YDR element in adjacent subunits are shown in
black. The carboxylate group of Asp9 forms a hydrogen bond with
the hydroxyl group of Tyr8 in the neighbouring a-subunit and
adopts a major part for the open axial channel. (d) Stereo
drawing of the closed channel of the a-ring from S. cerevisiae.
Contacts among residues of the YDR element in the a3 and a4
subunit, which maintain the regulatory gate in eukaryotes, are
shown in black sticks, whereas the N-terminal segments are
coloured in red.
|
|
|
|
|
|
The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2003,
327,
75-83)
copyright 2003.
|
|
|
|
|
|
|
