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PDBsum entry 1sop
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Structural protein
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PDB id
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1sop
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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 structure of the cys-Rich terminal domain of hydra minicollagen, Which is involved in disulfide networks of the nematocyst wall.
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Authors
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E.Pokidysheva,
A.G.Milbradt,
S.Meier,
C.Renner,
D.Häussinger,
H.P.Bächinger,
L.Moroder,
S.Grzesiek,
T.W.Holstein,
S.Ozbek,
J.Engel.
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Ref.
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J Biol Chem, 2004,
279,
30395-30401.
[DOI no: ]
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PubMed id
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Abstract
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The minicollagens found in the nematocysts of Hydra constitute a family of
invertebrate collagens with unusual properties. They share a common modular
architecture with a central collagen sequence ranging from 14 to 16 Gly-X-Y
repeats flanked by polyproline/hydroxyproline stretches and short terminal
domains that show a conserved cysteine pattern (CXXXCXXXCXXX-CXXXCC). The
minicollagen cysteine-rich domains are believed to function in a switch of the
disulfide connectivity from intra- to intermolecular bonds during maturation of
the capsule wall. The solution structure of the C-terminal fragment including a
minicollagen cysteine-rich domain of minicollagen-1 was determined in two
independent groups by 1H NMR. The corresponding peptide comprising the last 24
residues of the molecule was produced synthetically and refolded by oxidation
under low protein concentrations. Both presented structures are identical in
their fold and disulfide connections (Cys2-Cys18, Cys6-Cys14, and Cys10-Cys19)
revealing a robust structural motif that is supposed to serve as the
polymerization module of the nematocyst capsule.
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Figure 1.
FIG. 1. A, minicollagen-1 amino acid sequence and domain
structure. The propeptide sequence is blue, the MCRDs are red,
polyproline sequences are light green, the collagen repeat is
dark green. B, alignment of MCRDs in minicollagen molecules from
different cnidarians and in NOWA. MCol1h, minicollagen-1 Hydra;
MCol2h, minicollagen-2 Hydra (3); MColad, minicollagen Acropora
donei (2); MColac, minicollagen Acropora cervicornis (1);
MColap, minicollagen Acropora palmate (1); N and C, N-,
C-terminal. The sequence of the Cys-rich region of NOWA in Hydra
(NWh) starts with repeat 1 and terminates with repeat 8.
Residues in MCol1hC are numbered starting at the proline
preceding the first cysteine, and the same numbering was used in
the NMR structures. The highly conserved cysteine residues are
marked in red. Proline in position 12, which is conserved with
two exceptions, is marked in purple. The sequence of the
synthesized and investigated peptide is underlined.
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Figure 3.
FIG. 3. Stereo view of the same conformer as in Fig. 2 in
ribbon presentation. Only structure 2 is shown. Cysteines and
disulfide bonds are shown in yellow and Pro12 is in aquamarine.
Disulfide bonds (Cys2-Cys18, Cys6-Cys14 and Cys10-Cys19) as well
as the conserved Pro12 are indicated in ball-and-stick
representation. Dashed lines indicate the hydrogen bonds
identified by MOLMOL. These are bonds between Val5 (O) and Gln9
(HN), Val11 (O) and Cys14 (HN), and Pro15 (O) and Cys18 (HN).
The first H-bond belongs to the  -helix, others belong
to the three different turns. Pro12 induces a  I turn
from residues 11 to 14. All proline residues in the structure
can be shown to be in trans conformation from experimental
nuclear Overhauser effect distance information.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2004,
279,
30395-30401)
copyright 2004.
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