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PDBsum entry 5l3v
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Protein transport
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PDB id
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5l3v
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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 conserved regulation and adaptation of the signal recognition particle targeting complex.
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Authors
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K.Wild,
G.Bange,
D.Motiejunas,
J.Kribelbauer,
A.Hendricks,
B.Segnitz,
R.C.Wade,
I.Sinning.
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Ref.
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J Mol Biol, 2016,
428,
2880-2897.
[DOI no: ]
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PubMed id
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Abstract
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The signal recognition particle (SRP) is a ribonucleoprotein complex with a key
role in targeting and insertion of membrane proteins. The two SRP GTPases, SRP54
(Ffh in bacteria) and FtsY (SRĪ± in eukaryotes), form the core of the targeting
complex (TC) regulating the SRP cycle. The architecture of the TC and its
stimulation by RNA has been described for the bacterial SRP system while this
information is lacking for other domains of life. Here, we present the crystal
structures of the GTPase heterodimers of archaeal (Sulfolobus solfataricus),
eukaryotic (Homo sapiens), and chloroplast (Arabidopsis thaliana) SRP systems.
The comprehensive structural comparison combined with Brownian dynamics
simulations of TC formation allows for the description of the general blueprint
and of specific adaptations of the quasi-symmetric heterodimer. Our work defines
conserved external nucleotide-binding sites for SRP GTPase activation by RNA.
Structural analyses of the GDP-bound, post-hydrolysis states reveal a conserved,
magnesium-sensitive switch within the I-box. Overall, we provide a general model
for SRP cycle regulation by RNA.
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