Biosynthesis of coronatine: investigations of the biosynthesis of coronamic acid

Parry, Ronald J.; Lin, M. T.; Walker, Alan E.; Mhaskar, S. Y.

doi:10.1021/ja00005a069

Cited by 49 publications

(34 citation statements)

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“…Of the 10 residues that make up the specificity-conferring code, 7 are found in A domains that are specific for L-isoleucine, Lleucine, and L-valine. Both L-isoleucine and L-allo-isoleucine have been shown to be incorporated into CMA, but L-alloisoleucine, whose specificity-conferring code has not been defined yet, is a much more efficient precursor (25). The timing of the epimerization of L-isoleucine to L-allo-isoleucine is currently unknown.…”

Section: Resultsmentioning

confidence: 99%

“…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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confidence: 99%

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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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Section: Resultsmentioning

confidence: 99%

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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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“…The biosynthesis of CMA initially involves the isomerization of L-isoleucine to L-alloisoleucine, which is presumably followed by an oxidative cyclization to form the cyclopropane ring (41,42) (Fig. 1).…”

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The biosynthetic gene cluster for coronamic acid, an ethylcyclopropyl amino acid, contains genes homologous to amino acid-activating enzymes and thioesterases

Ullrich

Bender

1994

J Bacteriol

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Coronamic acid (CMA), an ethylcyclopropyl amino acid derived from isoleucine, functions as an intermediate in the biosynthesis of coronatine, a chlorosis-inducing phytotoxin produced by Pseudomonas syringae pv. glycinea PG4180. The DNA required for CMA biosynthesis (6.9 kb) was sequenced, revealing three distinct open reading frames (ORFs) which share a common orientation for transcription. The deduced amino acid sequence of a 2.7-kb ORF designated cmaA contained six core sequences and two conserved motifs which are present in a variety of amino acid-activating enzymes, including nonribosomal peptide synthetases. Furthermore, CmaA contained a spatial arrangement of histidine, aspartate, and arginine residues which are conserved in the ferrous active site of some nonheme iron(ll) enzymes which catalyze oxidative cyclizations.The deduced amino acid sequence of a 1.2-kb ORF designated cmaT was related to thioesterases of both procaryotic and eucaryotic origins. These data suggest that CMA assembly is similar to the thiotemplate mechanism of nonribosomal peptide synthesis. No significant similarities between a 0.9-kb ORF designated cmaU and other database entries were found. The start sites of two transcripts required for CMA biosynthesis were identified in the present study. pRG960sd, a vector containing a promoterless glucuronidase gene, was used to localize and study the promoter regions upstream of the two transcripts. Data obtained in the present study indicate that CMA biosynthesis is regulated at the transcriptional level by temperature.Coronatine (COR) is a chlorosis-inducing, non-host-specific phytotoxin produced by several Pseudomonas syringae pathovars and functions as an important virulence factor in the diseases incited by these bacteria (36,37,64). COR induces a number of responses in plants which can be reproduced by ethylene or indoleacetic acid, suggesting that the toxin alters host metabolism in a manner analogous to that of plant growth hormones (13,24,49). Recently, striking structural and functional homologies between COR, methyl jasmonate, and 12-oxo-phytodienoic acid were found, suggesting that COR mimics the octadecanoid signalling molecules of higher plants (15,19,63).COR consists of two distinct moieties, a polyketide component, coronafacic acid (CFA), and a cyclized amino acid, coronamic acid (CMA) (2-ethyl-1-aminocyclopropane 1-carboxylic acid). These are derived from separate biosynthetic pathways and coupled via amide bond formation ( Fig. 1) (42). Both moieties were previously shown to be required for the phytotoxic effects of COR (53, 63).The genes for COR biosynthesis in P. syringae pv. glycinea PG4180 are encoded within a 30-kb region of a 90-kb plasmid designated p4180A (67). Tn5 mutagenesis, phenotypic characterization, and feeding studies with exogenous CFA and CMA resulted in the recovery of mutants blocked in distinct biosynthetic steps (4). Genetic complementation studies with CMAdefective mutants and expression of CMA synthesis in another bacterium were used to localize a DNA...

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“…0001-7702 0 1993 SGM been partially determined (Mitchell, 1985;Parry et al, 1991;Parry & Mafoti, 1986;Young et al, 1992).…”

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confidence: 99%

Molecular characterization of field isolates of Pseudomonas syringae pv. glycinea differing in coronatine production

Ullrich

Bereswill

Völksch

et al. 1993

Journal of General Microbiology

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Coronatine-producing and non-producing strains of Pseudomonas syringae pv. gfycinea have been examined. We found a connection between copper resistance and synthesis of coronatine. Published data implied that these properties may be encoded on different plasmids. Production of coronatine and copper resistance were also found to be correlated for pv. glycinea in 19 field-isolates from leaf spots of plants in a soybean field and in 28 strains of a bacterial culture collection. Genomic diversity within pv. glycinea was investigated by plasmid profiling, DNA hybridization studies and PCR analysis. All strains unable to produce coronatine (cor-) were sensitive to copper ions and showed no homology to DNA from plasmid pSAY1, which carries a gene cluster for steps in coronatine production. In addition, cor-strains could be distinguished from coronatine-producing strains by a single unique band when amplified by random primer PCR. Plasmid profiles of strains isolated from field-populations during 1983, 1985 and 1990 showed that coronatine-producing and non-producing strains were present. The plasmid patterns also varied in 28 strains examined from a culture collection. No correlation between plasmid patterns and race specificity was observed. Cosmid pSAYl proved to be an effective probe for detection of the coronatine synthesis genes and also revealed polymorphisms in coronatine producing strains of pv. glycinea.

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Biosynthesis of coronatine: investigations of the biosynthesis of coronamic acid

Cited by 49 publications

References 1 publication

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

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

The biosynthetic gene cluster for coronamic acid, an ethylcyclopropyl amino acid, contains genes homologous to amino acid-activating enzymes and thioesterases

Molecular characterization of field isolates of Pseudomonas syringae pv. glycinea differing in coronatine production

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