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PDBsum entry 1j8m
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Signaling protein
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PDB id
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1j8m
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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 the conserved gtpase of srp54 from the archaeon acidianus ambivalens and its comparison with related structures suggests a model for the srp-Srp receptor complex.
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Authors
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G.Montoya,
K.Kaat,
R.Moll,
G.Schäfer,
I.Sinning.
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Ref.
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Structure, 2000,
8,
515-525.
[DOI no: ]
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PubMed id
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Abstract
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BACKGROUND: Protein targeting to the endoplasmic reticulum in eukaryotes and to
the cell membrane in prokaryotes is mediated by the signal recognition particle
(SRP) and its receptor (SR). Both contain conserved GTPase domains in the
signal-peptide-binding proteins (SRP54 and Ffh) and the SR proteins (SRalpha and
FtsY). These GTPases are involved in the regulation of protein targeting. Most
studies so far have focussed on the SRP machinery of mammals and bacteria,
leaving the SRP system of archaea less well understood. RESULTS: We report the
crystal structure of the conserved GTPase (NG-Ffh) from the thermophilic
archaeon Acidianus ambivalens at 2.0 A resolution and of the Thr112-->Ala
mutant, which is inactive in GTP hydrolysis. This is the first structure of an
SRP component from an archaeon and allows for a detailed comparison with related
structures from Escherichia coli and thermophilic bacteria. In particular,
differences in the conserved consensus regions for nucleotide binding and the
subdomain interfaces are observed, which provide information about the
regulation of the GTPase. These interactions allow us to propose a common
signalling mechanism for the SRP-SR system. CONCLUSIONS: The overall structure
of SRP-GTPases is well conserved between bacteria and archaea, which indicates
strong similarities in the regulation of the SRP-targeting pathway.
Surprisingly, structure comparisons identified a homodimeric ATP-binding protein
as the closest relative. A heterodimer model for the SRP-SR interaction is
presented.
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Figure 6.
Figure 6. Hydrophobic interactions close to the G4 region.
A conserved hydrophobic core is formed by Ile4, Phe289, Phe284,
Phe84, Met249, Leu259, Ile246 and Ile272.
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The above figure is
reprinted
by permission from Cell Press:
Structure
(2000,
8,
515-525)
copyright 2000.
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Secondary reference #1
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Title
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Crystallization and preliminary X-Ray diffraction studies on the conserved gtpase domain of the signal recognition particle from acidianus ambivalens.
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Authors
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G.Montoya,
K.Te kaat,
R.Moll,
G.Schäfer,
I.Sinning.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 1999,
55,
1949-1951.
[DOI no: ]
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PubMed id
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Figure 1.
Figure 1 Orthorhombic crystals of Ffh-NG from A. ambivalens.
Approximate dimensions are 0.2 × 0.2 × 0.5 mm (see text for
details).
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The above figure is
reproduced from the cited reference
with permission from the IUCr
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