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PDBsum entry 1qu0
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Metal binding protein
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PDB id
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1qu0
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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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The crystal structure of a laminin g-Like module reveals the molecular basis of alpha-Dystroglycan binding to laminins, Perlecan, And agrin.
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Authors
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E.Hohenester,
D.Tisi,
J.F.Talts,
R.Timpl.
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Ref.
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Mol Cell, 1999,
4,
783-792.
[DOI no: ]
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PubMed id
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Abstract
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Laminin G-like (LG) modules in the extracellular matrix glycoproteins laminin,
perlecan, and agrin mediate the binding to heparin and the cell surface receptor
alpha-dystroglycan (alpha-DG). These interactions are crucial to basement
membrane assembly, as well as muscle and nerve cell function. The crystal
structure of the laminin alpha 2 chain LG5 module reveals a 14-stranded beta
sandwich. A calcium ion is bound to one edge of the sandwich by conserved acidic
residues and is surrounded by residues implicated in heparin and alpha-DG
binding. A calcium-coordinated sulfate ion is suggested to mimic the binding of
anionic oligosaccharides. The structure demonstrates a conserved function of the
LG module in calcium-dependent lectin-like alpha-DG binding.
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Figure 3.
Figure 3. The Calcium Binding SiteStereo view of the
calcium binding site in α2LG5 in a similar view as Figure 2.
The calcium ion is shown as a pink sphere. Residues coordinating
to the calcium ion are labeled. Hydrogen bonds to the sulfate
ion (see text) are shown as grey lines. A water molecule is also
bound to the calcium ion but is not shown for clarity. The
electron density shown is a difference Fourier map of the Sm
derivative calculated with the final model phases and contoured
at 10σ.
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Figure 4.
Figure 4. Comparison of the LG Module and Pentraxin
Folds(A) α2LG5 and (B) human SAP ([17]). Disulfide bridges are
in yellow, and calcium ions are shown as pink spheres. The SAP
subunit is viewed approximately down the 5-fold axis of the SAP
pentamer. Regions involved in subunit contacts in the pentamer
are indicated by the black arrows.
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The above figures are
reprinted
by permission from Cell Press:
Mol Cell
(1999,
4,
783-792)
copyright 1999.
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Secondary reference #1
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Title
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Structural analysis and proteolytic processing of recombinant g domain of mouse laminin alpha2 chain.
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Authors
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J.F.Talts,
K.Mann,
Y.Yamada,
R.Timpl.
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Ref.
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Febs Lett, 1998,
426,
71-76.
[DOI no: ]
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PubMed id
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Figure 3.
Fig. 3. Electron microscopy after rotary shadowing of
recombinant LG fragments. A: LG2, B: LG4, C: LG4–5 and D:
LG1–3. The magnification bar (100 nm) is representative for
all sections.
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Figure 4.
Fig. 4. Immunoblotting of laminins with antisera raised
against the G domain of the mouse laminin α2 chain. The
antisera were against fragments LG1–3 (lanes 1, 2) and LG4–5
(lanes 3, 4). A mixture of human placenta laminin-2 and -4
(lanes 2, 3) and of mouse laminin-1 (lanes 1, 4) was used at 0.5
μg/lane. Samples were reduced and the electrophoresis was
calibrated with reduced marker proteins indicated in kDa in the
left margin.
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The above figures are
reproduced from the cited reference
with permission from the Federation of European Biochemical Societies
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Secondary reference #2
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Title
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The role of laminins in basement membrane function.
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Authors
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M.Aumailley,
N.Smyth.
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Ref.
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J Anat, 1998,
193,
1.
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PubMed id
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