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PDBsum entry 1cgd
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References listed in PDB file
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Key reference
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Title
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Hydration structure of a collagen peptide.
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Authors
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J.Bella,
B.Brodsky,
H.M.Berman.
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Ref.
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Structure, 1995,
3,
893-906.
[DOI no: ]
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PubMed id
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Abstract
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BACKGROUND: The collagen triple helix is a unique protein motif defined by the
supercoiling of three polypeptide chains in a polyproline II conformation. It is
a major domain of all collagen proteins and is also reported to exist in
proteins with host defense function and in several membrane proteins. The
triple-helical domain has distinctive properties. Collagen requires a high
proportion of the post-translationally modified imino acid 4-hydroxyproline and
water to stabilize its conformation and assembly. The crystal structure of a
collagen-like peptide determined to 1.85 Angstrum showed that these two features
may be related. RESULTS: A detailed analysis of the hydration structure of the
collagen-like peptide is presented. The water molecules around the carbonyl and
hydroxyprolyl groups show distinctive geometries. There are repetitive patterns
of water bridges that link oxygen atoms within a single peptide chain, between
different chains and between different triple helices. Overall, the water
molecules are organized in a semi-clathrate-like structure that surrounds and
interconnects triple helices in the crystal lattice. Hydroxyprolyl groups play a
crucial role in the assembly. CONCLUSIONS: The roles of hydroxyproline and
hydration are strongly interrelated in the structure of the collagen triple
helix. The specific, repetitive water bridges observed in this structure
buttress the triple-helical conformation. The extensively ordered hydration
structure offers a good model for the interpretation of the experimental results
on collagen stability and assembly.
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Figure 5.
Figure 5. Local hydrogen-bonding network around the four
interstitial waters, which are labeled W[1A], W[1B], W[1C] and
W[1D], shown in larger type. Figure 5. Local hydrogen-bonding
network around the four interstitial waters, which are labeled
W[1A], W[1B], W[1C] and W[1D], shown in larger type.
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Figure 6.
Figure 6. Space-filling representation for the progressive
hydration of the Gly→Ala peptide as seen in the crystal
structure. The views in the top row are perpendicular to the
molecular axis, whereas those in the bottom row are parallel to
the molecular axis at the same hydration level. (a) A view of
the naked triple helix; the three peptide chains are shown in
different colors. (b) Incorporation of the first shell of water
molecules, directly hydrogen bonded to carbonyl, hydroxyl or
even amide groups on the peptide surface. (c) Incorporation of
the second shell of water molecules, hydrogen bonded to the ones
in the first shell; the filling of the superhelical groove by
solvent molecules becomes more evident. (d) Third shell of water
molecules. Figure 6. Space-filling representation for the
progressive hydration of the Gly→Ala peptide as seen in the
crystal structure. The views in the top row are perpendicular to
the molecular axis, whereas those in the bottom row are parallel
to the molecular axis at the same hydration level. (a) A view of
the naked triple helix; the three peptide chains are shown in
different colors. (b) Incorporation of the first shell of water
molecules, directly hydrogen bonded to carbonyl, hydroxyl or
even amide groups on the peptide surface. (c) Incorporation of
the second shell of water molecules, hydrogen bonded to the ones
in the first shell; the filling of the superhelical groove by
solvent molecules becomes more evident. (d) Third shell of water
molecules.
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The above figures are
reprinted
by permission from Cell Press:
Structure
(1995,
3,
893-906)
copyright 1995.
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Secondary reference #1
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Title
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Crystal and molecular structure of a collagen-Like peptide at 1.9 a resolution.
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Authors
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J.Bella,
M.Eaton,
B.Brodsky,
H.M.Berman.
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Ref.
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Science, 1994,
266,
75-81.
[DOI no: ]
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PubMed id
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