Abstract
Necrotic (Nec) is an important component of the proteolytic cascade that activates the Toll-mediated immune response in Drosophila. The Nec protein is a member of the serpin (SERine Protease INhibitor) superfamily and is thought to regulate the cascade by inhibiting the serine protease Persephone. Nec was expressed in Escherichia coli, and the purified protein folded to the active native conformation required for protease inhibitory activity. Biochemical analysis showed that Nec had a broad inhibitory specificity and inhibited elastase, thrombin, and chymotrypsin-like proteases. It did not inhibit trypsin or kallikrein. These data show that Necrotic is likely to inhibit a wide range of proteases in Drosophila and that Nec has the specificity requirements to act as the physiological inhibitor of Persephone in vivo.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cloning, Molecular
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Drosophila / immunology*
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Drosophila / physiology
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Drosophila Proteins / chemistry
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Drosophila Proteins / immunology*
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Drosophila Proteins / physiology
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Endopeptidases / metabolism
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Escherichia coli / immunology
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Kinetics
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Lipopolysaccharides / immunology
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Mammals
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Models, Molecular
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Protein Structure, Secondary
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Receptors, Cell Surface / chemistry
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Receptors, Cell Surface / immunology*
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Receptors, Cell Surface / physiology
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Recombinant Proteins / chemistry
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Recombinant Proteins / immunology
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Sequence Deletion
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Serpins / immunology
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Serpins / physiology*
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Toll-Like Receptors
Substances
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Drosophila Proteins
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Lipopolysaccharides
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Receptors, Cell Surface
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Recombinant Proteins
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Serpins
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Tl protein, Drosophila
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Toll-Like Receptors
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nec protein, Drosophila
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Endopeptidases