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PDBsum entry 1kma
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Blood clotting
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PDB id
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1kma
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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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Interaction of kazal-Type inhibitor domains with serine proteinases: biochemical and structural studies.
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Authors
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B.Schlott,
J.Wöhnert,
C.Icke,
M.Hartmann,
R.Ramachandran,
K.H.Gührs,
E.Glusa,
J.Flemming,
M.Görlach,
F.Grosse,
O.Ohlenschläger.
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Ref.
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J Mol Biol, 2002,
318,
533-546.
[DOI no: ]
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PubMed id
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Abstract
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The interaction of domains of the Kazal-type inhibitor protein dipetalin with
the serine proteinases thrombin and trypsin is studied. The functional studies
of the recombinantly expressed domains (Dip-I+II, Dip-I and Dip-II) allow the
dissection of the thrombin inhibitory properties and the identification of Dip-I
as a key contributor to thrombin/dipetalin complex stability and its inhibitory
potency. Furthermore, Dip-I, but not Dip-II, forms a complex with trypsin
resulting in an inhibition of the trypsin activity directed towards protein
substrates. The high resolution NMR structure of the Dip-I domain is determined
using multi-dimensional heteronuclear NMR spectroscopy. Dip-I exhibits the
canonical Kazal-type fold with a central alpha-helix and a short two-stranded
antiparallel beta-sheet. Molecular regions essential for inhibitor complex
formation with thrombin and trypsin are identified. A comparison with molecular
complexes of other Kazal-type thrombin and trypsin inhibitors by molecular
modeling shows that the N-terminal segment of Dip-I fulfills the structural
prerequisites for inhibitory interactions with either proteinase and explains
the capacity of this single Kazal-type domain to interact with different
proteinases.
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Figure 2.
Figure 2. Thrombin inhibition by fusion proteins and
isolated dipetalin domains. The ordinate gives the relation of
the rate constants for substrate turnover by thrombin in the
presence of the test compound (v) and by thrombin only (v[0]).
The abscissa shows the concentrations of the tested proteins.
The lines in blue represent the fusion proteins H[6]-Sak-Dip-I (
 open
); H[6]-Sak-Dip-II (  triangle,
open ); H[6]-Sak-Dip-I+II (0m); lines in red represent the
isolated domains Dip-I ( open
); Dip-II ( triangle,
open ); Dip-I+II (0m); the black line represents H[6]-Sak-FXa (
 )
and the green line represents the complementation experiment
using Dip-I+Dip-II in 1:1 stoichiometric amounts ( ).
Error bars are indicated for each measurement.
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Figure 4.
Figure 4. [1H-15N] HSQC spectra of dipetalin-I (a) and the
trypsin/Dip-I complex (b). In the complexation experiments only
Dip-I was labeled with 15N.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2002,
318,
533-546)
copyright 2002.
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