Abstract
We purified a novel antibacterial substance from immunized adult Sarcophaga and determined its molecular structure to be N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine (5-S-GAD). We synthesized 5-S-GAD enzymatically from N-beta-alanyl-3, 4-dihydroxyphenylalanine (beta-Ala-Dopa) and reduced glutathione (GSH). The antibacterial activity of 5-S-GAD was found to be due to its production of H2O2. This is a novel antibacterial mechanism as it differs from the mechanisms of known antibacterial peptides. Two possible roles of 5-S-GAD in insect immunity, suppression of bacterial growth and activation of a Rel family transcription factor, are proposed.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Anti-Bacterial Agents / chemistry
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Anti-Bacterial Agents / isolation & purification*
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Anti-Bacterial Agents / pharmacology
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Dihydroxyphenylalanine / analogs & derivatives*
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Dihydroxyphenylalanine / chemistry
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Dihydroxyphenylalanine / isolation & purification
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Dihydroxyphenylalanine / pharmacology
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Diptera / chemistry*
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Diptera / immunology
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Diptera / metabolism
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Escherichia coli / drug effects
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Escherichia coli / immunology
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Glutathione / analogs & derivatives*
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Glutathione / chemistry
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Glutathione / isolation & purification
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Glutathione / pharmacology
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Hydrogen Peroxide / metabolism
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Immunization
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Molecular Structure
Substances
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Anti-Bacterial Agents
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N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine
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Dihydroxyphenylalanine
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Hydrogen Peroxide
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Glutathione