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PDBsum entry 1g7d
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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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Thioredoxin fold as homodimerization module in the putative chaperone erp29: nmr structures of the domains and experimental model of the 51 kda dimer.
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Authors
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E.Liepinsh,
M.Baryshev,
A.Sharipo,
M.Ingelman-Sundberg,
G.Otting,
S.Mkrtchian.
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Ref.
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Structure, 2001,
9,
457-471.
[DOI no: ]
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PubMed id
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Abstract
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BACKGROUND: ERp29 is a ubiquitously expressed rat endoplasmic reticulum (ER)
protein conserved in mammalian species. Fold predictions suggest the presence of
a thioredoxin-like domain homologous to the a domain of human protein disulfide
isomerase (PDI) and a helical domain similar to the C-terminal domain of P5-like
PDIs. As ERp29 lacks the double-cysteine motif essential for PDI redox activity,
it is suggested to play a role in protein maturation and/or secretion related to
the chaperone function of PDI. ERp29 self-associates into 51 kDa dimers and also
higher oligomers. RESULTS: 3D structures of the N- and C-terminal domains
determined by NMR spectroscopy confirmed the thioredoxin fold for the N-terminal
domain and yielded a novel all-helical fold for the C-terminal domain. Studies
of the full-length protein revealed a short, flexible linker between the two
domains, homodimerization by the N-terminal domain, and the presence of
interaction sites for the formation of higher molecular weight oligomers. A
gadolinium-based relaxation agent is shown to present a sensitive tool for the
identification of macromolecular interfaces by NMR. CONCLUSIONS: ERp29 is the
first eukaryotic PDI-related protein for which the structures of all domains
have been determined. Furthermore, an experimental model of the full-length
protein and its association states was established. It is the first example of a
protein where the thioredoxin fold was found to act as a specific
homodimerization module, without covalent linkages or supporting interactions by
further domains. A homodimerization module similar as in ERp29 may also be
present in homodimeric human PDI.
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Figure 6.
Figure 6. Different Stereorepresentations of Residues
155-256 of the NMR Solution Structure of the C-Terminal Domain
of ERp29All three representations show the structure in the same
orientation as in Figure 2. (a) Backbone trace of the conformer
with the lowest energy after restrained energy minimization. (b)
Ensemble of 20 conformers, using the backbone atoms of residues
160-250 for superposition. (c) Heavy-atom display of the
conformer of (a). The same color code was used as in Figure 4
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The above figure is
reprinted
by permission from Cell Press:
Structure
(2001,
9,
457-471)
copyright 2001.
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