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PDBsum entry 1dqc
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Antimicrobial protein
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PDB id
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1dqc
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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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Chitin-Binding proteins in invertebrates and plants comprise a common chitin-Binding structural motif.
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Authors
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T.Suetake,
S.Tsuda,
S.Kawabata,
K.Miura,
S.Iwanaga,
K.Hikichi,
K.Nitta,
K.Kawano.
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Ref.
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J Biol Chem, 2000,
275,
17929-17932.
[DOI no: ]
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PubMed id
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Abstract
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Tachycitin, a 73-residue polypeptide having antimicrobial activity is present in
the hemocyte of horseshoe crab (Tachypleus tridentatus). The first
three-dimensional structure of invertebrate chitin-binding protein was
determined for tachycitin using two-dimensional nuclear magnetic resonance
spectroscopy. The measurements indicate that the structure of tachycitin is
largely divided into N- and C-terminal domains; the former comprises a
three-stranded beta-sheet and the latter a two-stranded beta-sheet following a
short helical turn. The latter structural motif shares a significant tertiary
structural similarity with the chitin-binding domain of plant chitin-binding
protein. This result is thought to provide faithful experimental evidence to the
recent hypothesis that chitin-binding proteins of invertebrates and plants are
correlated by a convergent evolution process.
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Figure 1.
Fig. 1. Solution structure of tachycitin. A, stereo view
of the best-fit superposition of 25 structures of tachycitin
using backbone atoms (C^  , C,
and N) of residues 6-68. B, ribbon representation of the
minimized average structure of tachycitin. Disulfide bonds
(yellow),  -sheets
(blue), and an helical turn (red) are indicated. Drawings were
prepared using MOLMOL (26).
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Figure 3.
Fig. 3. Putative chitin-binding site of tachycitin
(Cys-40-Gly-60) superimposed onto the previously identified
chitin-binding site of hevein (Cys-12-Ser-32). The conserved
disulfide bonds are colored in green. Residues of Asn-47,
Tyr-49, and Val-52 in the -hairpin of
tachycitin (red) are superimposed onto the chitin-binding
residues of hevein (blue).
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2000,
275,
17929-17932)
copyright 2000.
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