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PDBsum entry 1smf
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Hydrolase/hydrolase inhibitor
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PDB id
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1smf
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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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Studies on an artificial trypsin inhibitor peptide derived from the mung bean trypsin inhibitor: chemical synthesis, Refolding, And crystallographic analysis of its complex with trypsin.
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Authors
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Y.Li,
Q.Huang,
S.Zhang,
S.Liu,
C.Chi,
Y.Tang.
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Ref.
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J Biochem (tokyo), 1994,
116,
18-25.
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PubMed id
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Abstract
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The active fragment with Lys at the reactive site of mung bean trypsin inhibitor
(MBILF) is composed of two peptide chains, A1 of 26 residues and A2 of 9
residues linked via two disulfide bonds. In the present study, a peptide of 22
residue comprising the sequence of chain A1 from position 3 to 24 was
synthesized by the solid-phase method. This synthetic peptide with six Cys
residues contains a reactive site at position Lys11I-Ser12I (I denotes an
inhibitor residue). Air oxidation and HPLC purification resulted in two
antitrypsin active components, SPC1 and SPC2. Neither SPC1 nor SPC2 can
stoichiometrically inhibit trypsin. The Ki values of SPC1 and SPC2 are 1.2 x
10(-7) and 4.0 x 10(-8) M, respectively. The complexes of SPC1 and SPC2 with
bovine beta-trypsin (BTRY) were crystallized by ammonium sulphate precipitation
at pH 6.4 and 6.0, respectively. The two crystals have the same crystal form
with space group P2(1)2(1)2(1) and cell dimension of a = 63.2(2) A, b = 63.5(6)
A, and c = 69.8(4) A. The crystal structure of one complex, SPC1-BTRY, was
determined and refined at 2.2 A resolution to a final R-value of 19.2%. From the
resulting electron density map, 9 residues of SPC1, from position 9I to 17I,
were identified clearly and three-dimension atomic model of the 9-residue
reactive loop formed by a disulfide bridge, Cys9I-Cys17I, was built. No electron
density corresponding to the other 13 residues was observed in the present
map.(ABSTRACT TRUNCATED AT 250 WORDS)
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