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PDBsum entry 2x31
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(+ 0 more)
188 a.a.
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(+ 0 more)
322 a.a.
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References listed in PDB file
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Key reference
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Title
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Atp-Induced conformational dynamics in the aaa+ motor unit of magnesium chelatase.
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Authors
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J.Lundqvist,
H.Elmlund,
R.P.Wulff,
L.Berglund,
D.Elmlund,
C.Emanuelsson,
H.Hebert,
R.D.Willows,
M.Hansson,
M.Lindahl,
S.Al-Karadaghi.
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Ref.
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Structure, 2010,
18,
354-365.
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PubMed id
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Abstract
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Mg-chelatase catalyzes the first committed step of the chlorophyll biosynthetic
pathway, the ATP-dependent insertion of Mg(2+) into protoporphyrin IX (PPIX).
Here we report the reconstruction using single-particle cryo-electron microscopy
of the complex between subunits BchD and BchI of Rhodobacter capsulatus
Mg-chelatase in the presence of ADP, the nonhydrolyzable ATP analog AMPPNP, and
ATP at 7.5 A, 14 A, and 13 A resolution, respectively. We show that the two AAA+
modules of the subunits form a unique complex of 3 dimers related by a
three-fold axis. The reconstructions demonstrate substantial differences between
the conformations of the complex in the presence of ATP and ADP, and suggest
that the C-terminal integrin-I domains of the BchD subunits play a central role
in transmitting conformational changes of BchI to BchD. Based on these data a
model for the function of magnesium chelatase is proposed.
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