Structure and Biosynthesis of Mangotoxin Produced by the Plant Pathogen Pseudomonas syringae
- 1Department of Chemistry University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
Abstract
Pathogenic bacteria interfere with plant metabolism through specialized metabolites and mechanisms. Mangotoxin was identified in 2003 from Pseudomonas syringae pv. syringae, which causes devastating diseases globally in various crops, including mango. Mangotoxin was found to inhibit arginine biosynthesis in tomato and Escherichia coli; however, its chemical structure remained unknown. We determined the structure of mangotoxin from the native bacterial producer P. syringae to be an alanine‐citrulline dipeptide that contains an internal alkyne on citrulline. We showed that mangotoxin also inhibits the growth of a multidrug‐resistant human pathogen Klebsiella pneumoniae strain. In vitro characterization of mangotoxin biosynthesis revealed that alkyne formation is catalyzed by a heme oxygenase‐like domain‐containing oxidase with a redox partner on a tripeptide intermediate. We discovered that the mangotoxin biosynthetic enzymes can couple various canonical and noncanonical amino acids into tripeptides and install two‐ or four‐electron oxidations on several tripeptides, providing a foundation for bioengineering of the pathway. Our work answered a two‐decade‐old question on the structure of an elusive toxin and will facilitate the elucidation of the molecular mechanism used by mangotoxin to inhibit amino acid metabolism in plants and bacteria.
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BibTeX
@article{murray2026structure,
title = {{Structure and Biosynthesis of Mangotoxin Produced by the Plant Pathogen Pseudomonas syringae}},
author = {Alexis H. Murray and Sohan Hazra and Ryan W. Mull and Erinn M. O'Neill and Bo Li},
journal = {Angewandte Chemie (International Ed. in English)},
year = {2026},
month = sep,
doi = {10.1002/anie.2211678},
url = {https://doi.org/10.1002/anie.2211678},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Structure and Biosynthesis of Mangotoxin Produced by the Plant Pathogen Pseudomonas syringae
AU - Alexis H. Murray
AU - Sohan Hazra
AU - Ryan W. Mull
AU - Erinn M. O'Neill
AU - Bo Li
PY - 2026
DA - 2026/09/22
JO - Angewandte Chemie (International Ed. in English)
DO - 10.1002/anie.2211678
UR - https://doi.org/10.1002/anie.2211678
AB - Pathogenic bacteria interfere with plant metabolism through specialized metabolites and mechanisms. Mangotoxin was identified in 2003 from Pseudomonas syringae pv. syringae, which causes devastating diseases globally in various crops, including mango. Mangotoxin was found to inhibit arginine biosynthesis in tomato and Escherichia coli; however, its chemical structure remained unknown. We determined the structure of mangotoxin from the native bacterial producer P. syringae to be an alanine‐citrulline dipeptide that contains an internal alkyne on citrulline. We showed that mangotoxin also inhibits the growth of a multidrug‐resistant human pathogen Klebsiella pneumoniae strain. In vitro characterization of mangotoxin biosynthesis revealed that alkyne formation is catalyzed by a heme oxygenase‐like domain‐containing oxidase with a redox partner on a tripeptide intermediate. We discovered that the mangotoxin biosynthetic enzymes can couple various canonical and noncanonical amino acids into tripeptides and install two‐ or four‐electron oxidations on several tripeptides, providing a foundation for bioengineering of the pathway. Our work answered a two‐decade‐old question on the structure of an elusive toxin and will facilitate the elucidation of the molecular mechanism used by mangotoxin to inhibit amino acid metabolism in plants and bacteria.
SN - 1433-7851
SN - 1521-3773
ER -