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PDBsum entry 2kiv
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Signaling protein
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PDB id
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2kiv
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References listed in PDB file
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Key reference
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Title
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A nuclear localization signal at the sam-Sam domain interface of aida-1 suggests a requirement for domain uncoupling prior to nuclear import.
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Authors
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A.Kurabi,
S.Brener,
M.Mobli,
J.J.Kwan,
L.W.Donaldson.
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Ref.
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J Mol Biol, 2009,
392,
1168-1177.
[DOI no: ]
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PubMed id
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Abstract
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The neuronal scaffolding protein AIDA-1 is believed to act as a convener of
signals arising at postsynaptic densities. Among the readily identifiable
domains in AIDA-1, two closely juxtaposed sterile alpha motif (SAM) domains and
a phosphotyrosine binding domain are located within the C-terminus of the
longest splice variant and exclusively in four shorter splice variants. As a
first step towards understanding the possible emergent properties arising from
this assembly of ligand binding domains, we have used NMR methods to solve the
first structure of a SAM domain tandem. Separated by a 15-aa linker, the two SAM
domains are fused in a head-to-tail orientation that has been observed in other
hetero- and homotypic SAM domain structures. The basic nuclear import signal for
AIDA-1 is buried at the interface between the two SAM domains. An observed
disparity between the thermal stabilities of the two SAM domains suggests a
mechanism whereby the second SAM domain decouples from the first SAM domain to
facilitate translocation of AIDA-1 to the nucleus.
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Figure 4.
Fig. 4. Effect of linker length on the orientation of the
SAM1 and SAM2 domains in the tandem. Protein structures were
solved using experimental data that had been transposed in
sequence number to reflect a successively shortened linker. The
RMSD difference between each linker variant and the wild-type
structure (length = 15) plotted against linker length.
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Figure 7.
Fig. 7. A diverse array of SAM domain partnerships. The
Ephrin kinase SAM domains have been crystallized in Head–Head
(involving helix 1) and Tail–Tail orientations (involving
helix 5). The Head–Tail orientation to which the AIDA-1 SAM
tandem belongs is shared with the heterotypic SAM partnerships
of human/Drosophila CNK2/HYP, Drosophila Ph/Scm, and S.
cerevisiae Ste11/Ste50, among others. PDB codes of the relevant
structures are indicated.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2009,
392,
1168-1177)
copyright 2009.
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