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PDBsum entry 3bx1
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Hydrolase/hydrolase inhibitor
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PDB id
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3bx1
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References listed in PDB file
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Key reference
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Title
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Structural and mutational analyses of the interaction between the barley alpha-Amylase/subtilisin inhibitor and the subtilisin savinase reveal a novel mode of inhibition.
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Authors
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P.O.Micheelsen,
J.Vévodová,
L.De maria,
P.R.Ostergaard,
E.P.Friis,
K.Wilson,
M.Skjøt.
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Ref.
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J Mol Biol, 2008,
380,
681-690.
[DOI no: ]
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PubMed id
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Abstract
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Subtilisins represent a large class of microbial serine proteases. To date,
there are three-dimensional structures of proteinaceous inhibitors from three
families in complex with subtilisins in the Protein Data Bank. All interact with
subtilisin via an exposed loop covering six interacting residues. Here we
present the crystal structure of the complex between the Bacillus lentus
subtilisin Savinase and the barley alpha-amylase/subtilisin inhibitor (BASI).
This is the first reported structure of a cereal Kunitz-P family inhibitor in
complex with a subtilisin. Structural analysis revealed that BASI inhibits
Savinase in a novel way, as the interacting loop is shorter than loops
previously reported. Mutational analysis showed that Thr88 is crucial for the
inhibition, as it stabilises the interacting loop through intramolecular
interactions with the BASI backbone.
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Figure 2.
Fig. 2. Subtilisin inhibition modes. Upper panel: The
subtilisin surface is shown in white, and residues in contact
with the inhibitor are shown in blue. Residues of the inhibitor
spanning subsites P4′ to P9 are shown as red sticks. Lower
panel: Zoom-in on the interaction. P5–P2′ inhibitor residues
and interacting subtilisin residues are shown as sticks;
subtilisin residues, active site residues and inhibitor residues
are shown in blue, yellow and red, respectively. β-Strands are
shown as arrows. (a) BASI (this work, chains A and C). (b) SSI
(2SIC). (c) CI-2 (2SNI). (d) OMTKY3 (1YU6, chains A and C).
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Figure 4.
Fig. 4. BASI plasticity II. The side chains of the
interacting residues are shown as sticks; BASI residues are
shown in red, and the surface of Savinase is shown in blue. (a)
BASI–Savinase, corresponding to chains A and C. (b)
BASI–Savinase, corresponding to chains B and D of this work.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2008,
380,
681-690)
copyright 2008.
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