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PDBsum entry 1vf6
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Protein binding/protein transport
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PDB id
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1vf6
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Contents |
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58 a.a.
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60 a.a.
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51 a.a.
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48 a.a.
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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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Structural basis for l27 domain-Mediated assembly of signaling and cell polarity complexes.
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Authors
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Y.Li,
D.Karnak,
B.Demeler,
B.Margolis,
A.Lavie.
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Ref.
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EMBO J, 2004,
23,
2723-2733.
[DOI no: ]
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PubMed id
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Abstract
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L27 is a protein-binding domain that can assemble essential proteins for
signaling and cell polarity into complexes by interacting in a heterodimeric
manner. One of these protein complexes is the PATJ/PALS1/Crumbs tripartite
complex, which is crucial for the establishment and maintenance of cell
polarity. To reveal the structural basis underlining the obligate
heterodimerization, we have determined the crystal structure of the
PALS1-L27N/PATJ-L27 heterodimer complex. Each L27 domain is composed of three
helices. The two L27 domains heterodimerize by building a compact structure
consisting of a four-helix bundle formed by the first two helices of each L27
domain and one coiled-coil formed by the third helix of each domain. The large
hydrophobic packing interactions contributed by all the helices of both L27
domains predominantly drive the heterodimer formation, which is likely to be a
general feature of L27 domains. Combined with mutational studies, we can begin
to understand the structural basis for the specificity of L27 binding pairs. Our
results provide unique insights into L27 domain heterodimer complex, which is
critical for cell polarization.
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Figure 2.
Figure 2 Structure of the L27[PALS1N]/L27[PATJ] heterodimer. (A)
Overall structure of the two PALS1 -PATJ L27 domain complexes
present in the crystallographic asymmetric unit. Red/yellow:
PALS1; blue/green: PATJ. (B) Ribbon diagram of the SAP97 L27 and
the mLin2 L27N complex solved by NMR (Feng et al, 2004). Based
on sequence alignment (Figure 1B) and domain classification, the
SAP97 L27 domain is colored in blue and green, analogous to the
PATJ L27 domain, whereas mLin2 is colored in red and yellow,
analogous to the PALS1 L27N domain. Note the similarity in the
heterodimer formation to that of the L27[PALS1N]/L27[PATJ]
heterodimer, and the striking difference in the interface
between the two heterodimers. (C) Overlay of the two
heterodimers in the asymmetric unit based on C  atoms
belonging to Helix 1 and Helix 2 of the PATJ L27 domain.
Red/yellow: PALS1; blue/green: PATJ. (D) Overlay of the two
heterodimers in the asymmetric unit based on C atoms
from Helix 3 of the PATJ L27 domain. All structural figures were
generated with MOLSCRIPT (Kraulis, 1991) and RASTER3D (Merrit
and Murphy, 1994).
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Figure 3.
Figure 3 Comparison of the L27[PALS1N] and L27[PATJ] domains.
Ribbon diagram of the PATJ L27 domain (A) and of the PALS1 L27
domain (B). (C) Stereoview of a C trace
of the overlaid L27[PALS1N] and L27[PATJ] domains. Red/yellow:
PALS1; blue/green: PATJ. (The red and blue belong to one
heterodimer in the asymmetric unit, and yellow and green belong
to the other copy.) 
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The above figures are
reprinted
from an Open Access publication published by Macmillan Publishers Ltd:
EMBO J
(2004,
23,
2723-2733)
copyright 2004.
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