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PDBsum entry 1f16
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Contents |
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* Residue conservation analysis
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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 of bax: coregulation of dimer formation and intracellular localization.
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Authors
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M.Suzuki,
R.J.Youle,
N.Tjandra.
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Ref.
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Cell, 2000,
103,
645-654.
[DOI no: ]
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PubMed id
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Abstract
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Apoptosis is stimulated by the insertion of Bax from the cytosol into
mitochondrial membranes. The solution structure of Bax, including the putative
transmembrane domain at the C terminus, was determined in order to understand
the regulation of its subcellular location. Bax consists of 9 alpha helices
where the assembly of helices alpha1 through alpha 8 resembles that of the
apoptosis inhibitor, Bcl-x(L). The C-terminal alpha 9 helix occupies the
hydrophobic pocket proposed previously to mediate heterodimer formation and
bioactivity of opposing members of the Bcl-2 family. The Bax structure shows
that the orientation of helix alpha 9 provides simultaneous control over its
mitochondrial targeting and dimer formation.
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Figure 3.
Figure 3. Structure Comparison between Bax and Bcl-x[L]Two
different views of (A) Bax, (B) Bcl-x[L], and (C) Bcl-x[L]
complexed with Bak BH3 peptide are presented, a view straight
down the central hydrophobic helix α5 (top panels) and a view
from the side of the protein (bottom panels). The atomic
coordinates of Bcl-x[L] and the Bcl-x[L]–peptide complex were
obtained from the Protein Data Bank with ID codes 1MAZ and 1BXL,
respectively. The BH1, BH2, BH3, and BH4 domains are shown in
cyan, magenta, red, and blue, respectively. Helix α1 in Bax,
which corresponds to BH4 containing helix in Bcl-x[L], is shown
in purple. The C-terminal helix of Bax and the Bak BH3 peptide
are shown in green. The C-terminal 24 residues of Bcl-x[L] were
deleted in both structural studies of free and complexed
Bcl-x[L]. The side chain of hydrophobic residues of Bak BH3
peptide (Val^74, Leu^78, Ile^81, and Ile^85) for stabilizing the
complex formation between Bcl-x[L] and Bak BH3 peptide and those
of corresponding hydrophobic residues of Bax BH3 domain (Leu^60,
Leu^63, Ile^66, Leu^70) are represented by balls and sticks.
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Figure 6.
Figure 6. The Orientation of the C-terminal HelixA close-up
view of the Bax C-terminal helix and the hydrophobic pocket is
shown. The side chains of the residues in the C-terminal helix
are represented by balls and sticks. Solvent exposed side chains
are shown in cyan. Magenta balls represent oxygen atom in
threonines and serine. A surface representation of the pocket is
colored red, purple, and yellow to represent negative, positive,
and hydrophobic residues, respectively.
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The above figures are
reprinted
by permission from Cell Press:
Cell
(2000,
103,
645-654)
copyright 2000.
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