Investigations of Coronatine Biosynthesis. Elucidation of the Mode of Incorporation of Pyruvate into Coronafacic Acid

Parry, Ronald J.; Jiralerspong, Sao; Mhaskar, S. Y.; Alemany, Lawrence B.; Willcott, Robert

doi:10.1021/ja9536330

Cited by 26 publications

(14 citation statements)

References 13 publications

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“…Precursor feeding studies with 13 C-labeled substrates demonstrated that CFA is a novel polyketide synthesized from C-2 and C-3 of pyruvate, three acetate units, and one butyrate unit (7). Further studies indicated that the pyruvate used for CFA biosynthesis is converted to ␣-ketoglutarate before incorporation into CFA (38). Since C-1 of pyruvate is not incorporated into CFA, C-1 of ␣-ketoglutarate must be lost at some stage in CFA biosynthesis.…”

Section: Resultsmentioning

confidence: 99%

Biosynthesis of the Pseudomonas polyketide coronafacic acid requires monofunctional and multifunctional polyketide synthase proteins

Rangaswamy

Jiralerspong

Parry

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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Coronafacic acid (CFA) is the polyketide component of the phytotoxin coronatine, a virulence factor of the plant pathogen Pseudomonas syringae. Our current knowledge of polyketide biosynthesis largely is based on the analysis of polyketide synthases (PKSs) in actinomycetes and other Gram-positive bacteria. Consequently, the cloning and characterization of the CFA biosynthetic gene cluster will contribute significantly to our knowledge of polyketide synthesis in Pseudomonas. In this report, we describe two genes in the CFA biosynthetic gene cluster that encode PKSs that are structurally and functionally similar to the multifunctional modular PKSs, which catalyze the synthesis of macrolide antibiotics. The CFA PKS genes were overproduced in Escherichia coli and shown to cross-react with antisera made to a modular PKS involved in erythromycin synthesis. A scheme for CFA biosynthesis is presented that incorporates the activities of all proteins in the CFA PKS. In this report a gene cluster encoding a pseudomonad polyketide has been completely sequenced and the deduced gene functions have been used to develop a biosynthetic scheme.

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Section: Resultsmentioning

confidence: 99%

Biosynthesis of the Pseudomonas polyketide coronafacic acid requires monofunctional and multifunctional polyketide synthase proteins

Rangaswamy

Jiralerspong

Parry

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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“…5). Recent studies have suggested that the pyruvate used for CFA biosynthesis is converted into ␣-ketoglutarate before incorporation to CFA and that ␣-ketoglutarate may serve as the starter unit for CFA assembly (194). Little information is available about potential intermediates in the biosynthetic route to CFA, probably because such intermediates remain enzyme bound.…”

Section: Generalized Biosynthetic Routementioning

confidence: 99%

Pseudomonas syringaePhytotoxins: Mode of Action, Regulation, and Biosynthesis by Peptide and Polyketide Synthetases

Bender

Alarcón-Chaidez

Gross

1999

Microbiol Mol Biol Rev

766

505

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SUMMARY Coronatine, syringomycin, syringopeptin, tabtoxin, and phaseolotoxin are the most intensively studied phytotoxins of Pseudomonas syringae, and each contributes significantly to bacterial virulence in plants. Coronatine functions partly as a mimic of methyl jasmonate, a hormone synthesized by plants undergoing biological stress. Syringomycin and syringopeptin form pores in plasma membranes, a process that leads to electrolyte leakage. Tabtoxin and phaseolotoxin are strongly antimicrobial and function by inhibiting glutamine synthetase and ornithine carbamoyltransferase, respectively. Genetic analysis has revealed the mechanisms responsible for toxin biosynthesis. Coronatine biosynthesis requires the cooperation of polyketide and peptide synthetases for the assembly of the coronafacic and coronamic acid moieties, respectively. Tabtoxin is derived from the lysine biosynthetic pathway, whereas syringomycin, syringopeptin, and phaseolotoxin biosynthesis requires peptide synthetases. Activation of phytotoxin synthesis is controlled by diverse environmental factors including plant signal molecules and temperature. Genes involved in the regulation of phytotoxin synthesis have been located within the coronatine and syringomycin gene clusters; however, additional regulatory genes are required for the synthesis of these and other phytotoxins. Global regulatory genes such as gacS modulate phytotoxin production in certain pathovars, indicating the complexity of the regulatory circuits controlling phytotoxin synthesis. The coronatine and syringomycin gene clusters have been intensively characterized and show potential for constructing modified polyketides and peptides. Genetic reprogramming of peptide and polyketide synthetases has been successful, and portions of the coronatine and syringomycin gene clusters could be valuable resources in developing new antimicrobial agents.

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“…These two moieties are produced by different biosynthetic pathways (26). Three acetate units, one butyrate unit, and a four-carbon unit that is derived from glutamic acid are combined to form CFA (27), while CMA is derived from L-isoleucine via L-allo-isoleucine which is oxidatively cyclized to form the cyclopropane ring (25). A ligase is then presumed to join CFA to CMA and produce COR via formation of an amide bond (2,18).…”

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Characterization of CmaA, an Adenylation-Thiolation Didomain Enzyme Involved in the Biosynthesis of Coronatine

et al. 2004

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Several pathovars of Pseudomonas syringae produce the phytotoxin coronatine (COR), which contains an unusual amino acid, the 1-amino-2-ethylcyclopropane carboxylic acid called coronamic acid (CMA), which is covalently linked to a polyketide-derived carboxylic acid, coronafacic acid, by an amide bond. The region of the COR biosynthetic gene cluster proposed to be responsible for CMA biosynthesis was resequenced, and errors in previously deposited cmaA sequences were corrected. These efforts allowed overproduction of P. syringae pv. glycinea PG4180 CmaA in P. syringae pv. syringae FF5 as a FLAG-tagged protein and overproduction of P. 3 H]allo-isoleucine, followed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis analysis. It is postulated that the L-allo-isoleucine covalently tethered to CmaA serves as the substrate for additional enzymes in the CMA biosynthetic pathway that catalyze cyclopropane ring formation, which is followed by thiolester hydrolysis, yielding free CMA. The availability of catalytically active CmaA should facilitate elucidation of the details of the subsequent steps in the formation of this novel cyclopropyl amino acid.

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Investigations of Coronatine Biosynthesis. Elucidation of the Mode of Incorporation of Pyruvate into Coronafacic Acid

Cited by 26 publications

References 13 publications

Biosynthesis of the Pseudomonas polyketide coronafacic acid requires monofunctional and multifunctional polyketide synthase proteins

Biosynthesis of the Pseudomonas polyketide coronafacic acid requires monofunctional and multifunctional polyketide synthase proteins

Pseudomonas syringaePhytotoxins: Mode of Action, Regulation, and Biosynthesis by Peptide and Polyketide Synthetases

Characterization of CmaA, an Adenylation-Thiolation Didomain Enzyme Involved in the Biosynthesis of Coronatine

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