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PDBsum entry 1z87
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Protein binding
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PDB id
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1z87
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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 the split ph domain and distinct lipid-Binding properties of the ph-Pdz supramodule of alpha-Syntrophin.
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Authors
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J.Yan,
W.Wen,
W.Xu,
J.F.Long,
M.E.Adams,
S.C.Froehner,
M.Zhang.
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Ref.
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Embo J, 2005,
24,
3985-3995.
[DOI no: ]
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PubMed id
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Abstract
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Pleckstrin homology (PH) domains play diverse roles in cytoskeletal dynamics and
signal transduction. Split PH domains represent a unique subclass of PH domains
that have been implicated in interactions with complementary partial PH domains
'hidden' in many proteins. Whether partial PH domains exist as independent
structural units alone and whether two halves of a split PH domain can fold
together to form an intact PH domain are not known. Here, we solved the
structure of the PH(N)-PDZ-PH(C) tandem of alpha-syntrophin. The split PH domain
of alpha-syntrophin adopts a canonical PH domain fold. The isolated partial PH
domains of alpha-syntrophin, although completely unfolded, remain soluble in
solution. Mixing of the two isolated domains induces de novo folding and yields
a stable PH domain. Our results demonstrate that two complementary partial PH
domains are capable of binding to each other to form an intact PH domain. We
further showed that the PH(N)-PDZ-PH(C) tandem forms a functionally distinct
supramodule, in which the split PH domain and the PDZ domain function
synergistically in binding to inositol phospholipids.
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Figure 3.
Figure 3 Folding and interaction of the two isolated, partial PH
domain fragments. (A) SDS-PAGE showing the purification of the
joined PH[N]-'C'-PH[C] domain and cleavage of the domain into
PH[N] and PH[C] fragments. (B) Overlay plot of the 1H, 15N HSQC
spectra of the joined PH[N]-'C'-PH[C] (black) and its protease
cleaved form (red). 1H, 15N HSQC spectra of the isolated PH[N]
(C) and PH[C] (D) fragments. (E) Overlay plot of the 1H, 15N
HSQC spectra of the joined PH[N]-'C'-PH[C] (black) and the 1:1
mixture of the two halves of the split PH domain (red).
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Figure 5.
Figure 5 Lipid-binding specificity of the PH[N]-PDZ-PH[C]
supramodule using phospholipid strip overlay assay. (A) Binding
of the PH[N]-PDZ-PH[C] tandem to the phospholipids spotted on a
cellulose membrane. The amount of lipid per spot was 100 pmol.
Abbreviations for the lipids: S1P: sphingosine-1-phosphate; LPA:
lysophosphatidic acid; LPC: lysophosphocholine; PE:
phosphatidylethanolamine; PS: phosphatidylserine; PA:
phosphatidic acid; PC: phosphatidylcholine; PtdIns:
phosphatidylinositol. The amount of protein used in the assay is
0.5  g/ml.
(B) Binding isotherms of PH[N]-PDZ-PH[C] with PC/PS liposomes
containing either 10 or 20% PI(3,5)P[2]. (C) Identification of
the residues in the split PH domain of the PH[N]-PDZ-PH[C]
tandem that are involved in the lipid binding.
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The above figures are
reprinted
by permission from Macmillan Publishers Ltd:
Embo J
(2005,
24,
3985-3995)
copyright 2005.
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