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PDBsum entry 1zka
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Transcription
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PDB id
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1zka
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References listed in PDB file
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Key reference
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Title
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Nf-Kappab relb forms an intertwined homodimer.
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Authors
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D.B.Huang,
D.Vu,
G.Ghosh.
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Ref.
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Structure, 2005,
13,
1365-1373.
[DOI no: ]
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PubMed id
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Abstract
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The X-ray structure of the RelB dimerization domain (DD) reveals that the RelBDD
assumes an unexpected intertwined fold topology atypical of other NF-kappaB
dimers. All typical NF-kappaB dimers are formed by the association of two
independently folded immunoglobulin (Ig) domains. In RelBDD, two polypeptides
reconstruct both Ig domains in the dimer with an extra beta sheet connecting the
two domains. Residues most critical to NF-kappaB dimer formation are invariant
in RelB, and Y300 plays a positive role in RelBDD dimer formation. The presence
of RelB-specific nonpolar residues at the surface removes several intradomain
surface hydrogen bonds that may render the domain fold unstable. Intertwining
may stabilize the RelBDD homodimer by forming the extra beta sheet. We show
that, as in the crystal, RelB forms an intertwined homodimer in solution. We
suggest that the transiently stable RelB homodimer might prevent its rapid
degradation, allowing for heterodimer formation with p50 and p52.
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Figure 2.
Figure 2. Detailed Structural Comparisons between the
RelBDD Homodimer and the p50DD Homodimer
(A) Overlay of the
"b"-"e" b sheets from p50DD and RelBDD . This view is generated
by rotating the superimposed Ig-like folds (right) 90° around
the long axis of the fold, as shown in Figure 1E. All of the p50
(green) residues are involved in the dimer interface. RelB is
shown in red and gray, respectively, for the two chains in the b
sheet.
(B and C) Comparison of the orientations of
homologous Tyr at the subunit interfaces of the RelBDD and p50DD
dimers, respectively.
(D) The b turn connecting b strands
"c'" and "e" and the residues present in the turn of p50DD are
shown.
(E) The same segment as in (C) in RelBDD is shown.
The turn is converted into a strand ("d"), and the two opposing
strands connecting the two Ig-like folds of RelBDD are
presented. The side chain conformations of His and Gln are
completely different in the two dimers.
(F) The hydrogen
bonding pattern in the swapped region of the MLAM mutant of
p50DD.
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The above figure is
reprinted
by permission from Cell Press:
Structure
(2005,
13,
1365-1373)
copyright 2005.
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