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PDBsum entry 3esl
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References listed in PDB file
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Key reference
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Title
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The crystal structure of the n-Terminal region of bub1 provides insight into the mechanism of bub1 recruitment to kinetochores.
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Authors
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V.M.Bolanos-Garcia,
T.Kiyomitsu,
S.D'Arcy,
D.Y.Chirgadze,
J.G.Grossmann,
D.Matak-Vinkovic,
A.R.Venkitaraman,
M.Yanagida,
C.V.Robinson,
T.L.Blundell.
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Ref.
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Structure, 2009,
17,
105-116.
[DOI no: ]
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PubMed id
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Abstract
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The interaction of the central mitotic checkpoint component BUB1 with the
mitotic kinetochore protein Blinkin is required for the kinetochore localization
and function of BUB1 in the mitotic spindle assembly checkpoint, the regulatory
mechanism of the cell cycle that ensures the even distribution of chromosomes
during the transition from metaphase to anaphase. Here, we report the 1.74 A
resolution crystal structure of the N-terminal region of BUB1. The structure is
organized as a tandem arrangement of three divergent units of the
tetratricopeptide motif. Functional assays in vivo of native and site-specific
mutants identify the residues of human BUB1 important for the interaction with
Blinkin and define one region of potential therapeutic interest. The structure
provides insight into the molecular basis of Blinkin-specific recognition by
BUB1 and, on a broader perspective, of the mechanism that mediates kinetochore
localization of BUB1 in checkpoint-activated cells.
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Figure 3.
Figure 3. Overall Structure of the N-Terminal Domain of BUB1
(A) The two molecules observed in the crystal asymmetric
unit associate to form a dimer with noncrystallographic two-fold
symmetry.
(B) The structure viewed 90° rotated along
the minor axis.
(C) Electron density for α helices H5, H6,
H7, and H9 and the connecting loop (after density modification)
contoured at 1.4 σ. The final, refined model is shown using a
ball-and-stick representation. The α helices, loops, and side
chains are clearly visible in the initial map. Water molecules
are shown as red spheres.
(D) Ribbon diagram showing that
this domain consists of ten α helices with a core arrangement
of a triple repeat of the TPR motif (TPR1 orange; TPR2 magenta;
TPR3 cyan).
(E,F) Superposition of the three TPRs of
Sc-BUB1[(29-230)]. Each molecule representation was generated
with Pymol (DeLano, 2002).
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Figure 5.
Figure 5. Analysis of the Hs-BUB1-Blinkin Interaction
(A) Yeast two-hybrid analysis of diverse Hs-BUB1 mutants. The
effect of the mutant P23G could not be established as it showed
self-activation.
(B) Projection of residues important for
binding Blinkin onto the protein surface (salmon color).
Residues whose mutation did not compromise the binding with
Blinkin are shown in blue.
(C) Mapping of Hs-BUB1 mutations
associated with cancer. Residues absent in the deletion mutant
Δ76–141 are shown in green and residues E36D, A130S, and
H151D in brown.
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The above figures are
reprinted
from an Open Access publication published by Cell Press:
Structure
(2009,
17,
105-116)
copyright 2009.
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