scholarly journals Identification of the Biosynthetic Gene Cluster for 3-Methylarginine, a Toxin Produced by Pseudomonas syringae pv. syringae 22d/93

2010 ◽  
Vol 76 (8) ◽  
pp. 2500-2508 ◽  
Author(s):  
S. D. Braun ◽  
J. Hofmann ◽  
A. Wensing ◽  
M. S. Ullrich ◽  
H. Weingart ◽  
...  

ABSTRACT The epiphyte Pseudomonas syringae pv. syringae 22d/93 (Pss22d) produces the rare amino acid 3-methylarginine (MeArg), which is highly active against the closely related soybean pathogen Pseudomonas syringae pv. glycinea. Since these pathogens compete for the same habitat, Pss22d is a promising candidate for biocontrol of P. syringae pv. glycinea. The MeArg biosynthesis gene cluster codes for the S-adenosylmethionine (SAM)-dependent methyltransferase MrsA, the putative aminotransferase MrsB, and the amino acid exporter MrsC. Transfer of the whole gene cluster into Escherichia coli resulted in heterologous production of MeArg. The methyltransferase MrsA was overexpressed in E. coli as a His-tagged protein and functionally characterized (Km , 7 mM; k cat, 85 min−1). The highly selective methyltransferase MrsA transfers the methyl group from SAM into 5-guanidino-2-oxo-pentanoic acid to yield 5-guanidino-3-methyl-2-oxo-pentanoic acid, which then only needs to be transaminated to result in the antibiotic MeArg.

1997 ◽  
Vol 43 (6) ◽  
pp. 517-525 ◽  
Author(s):  
David A. Palmer ◽  
Carol L. Bender ◽  
Shashi B. Sharma

Pseudomonas syringae pv. glycinea PG4180 produces coronatine (COR), a chlorosis-inducing phytotoxin that consists of the polyketide coronafacic acid (CFA) coupled via an amide bond to the ethylcyclopropyl amino acid coronamic acid (CMA). Both CFA and CMA function as intermediates in the pathway to coronatine, and genes encoding their synthesis have been localized; however, the precise factors that regulate the production of COR and its precursors remain unclear. In the present study, a λ delivery system for Tn5-gusA5 was developed and used to obtain transcriptional fusions in the COR gene cluster. Selected carbon (fructose and xylose) and amino acid (isoleucine and valine) sources significantly decreased COR biosynthesis at the transcriptional level. Transcriptional activity in the COR gene cluster was temperature dependent with maximal expression at 18–24 °C and significantly less expression at 14 and 30 °C. Interestingly, changes in osmolarity and the addition of complex carbon and nitrogen sources to the growth medium did not significantly affect COR gene expression, although both factors significantly impacted the quantity of COR produced. These results indicate that multiple factors impact COR production and only some of these directly affect transcription in the COR gene cluster.Key words: transcriptional fusion, glucuronidase, gene expression, reporter gene.


2015 ◽  
Vol 28 (4) ◽  
pp. 443-454 ◽  
Author(s):  
Joanna K. Fyans ◽  
Mead S. Altowairish ◽  
Yuting Li ◽  
Dawn R. D. Bignell

Streptomyces scabies is an important causative agent of common scab disease of potato tubers and other root crops. The primary virulence factor produced by this pathogen is a phytotoxic secondary metabolite called thaxtomin A, which is essential for disease development. In addition, the genome of S. scabies harbors a virulence-associated biosynthetic gene cluster called the coronafacic acid (CFA)-like gene cluster, which was previously predicted to produce metabolites that resemble the Pseudomonas syringae coronatine (COR) phytotoxin. COR consists of CFA linked to an ethylcyclopropyl amino acid called coronamic acid, which is derived from L-allo-isoleucine. Using a combination of genetic and chemical analyses, we show that the S. scabies CFA-like gene cluster is responsible for producing CFA-L-isoleucine as the major product as well as other minor COR-like metabolites. Production of the metabolites was shown to require the cfl gene, which is located within the CFA-like gene cluster and encodes an enzyme involved in ligating CFA to its amino acid partner. CFA-L-isoleucine purified from S. scabies cultures was shown to exhibit bioactivity similar to that of COR, though it was found to be less toxic than COR. This is the first report demonstrating the production of coronafacoyl phytotoxins by S. scabies, which is the most prevalent scab-causing pathogen in North America.


Author(s):  
Daniel Carretero Molina ◽  
Francisco Javier Ortiz-Lopez ◽  
Jesús Martín ◽  
Ignacio González ◽  
Marina Sánchez-Hidalgo ◽  
...  

Pentaminomycins F-H, a group of three new hydroxyarginine-containing cyclic pentapeptides, were isolated from cultures of a <i>Streptomyces cacaoi</i> subsp. <i>cacaoi</i> strain along with the known pentaminomycins A-E. The structures of the new peptides were determined by a combination of mass spectrometry and NMR and Marfey's analyses. Among them, pentaminomycins F and G were shown to contain in their structures the rare amino acid 3-(2-pyridyl)-alanine. This finding represents the first reported example of non-ribosomal peptides containing this residue. The LDLLD chiral sequence found for the three compounds was in agreement with that reported for previously isolated pentaminomycins and consistent with the epimerization domains present in the putative non-robosomal peptide synthetase (NRPS) biosynthetic gene cluster.<br>


2010 ◽  
Vol 55 (3) ◽  
pp. 974-982 ◽  
Author(s):  
Qiulin Wu ◽  
Jingdan Liang ◽  
Shuangjun Lin ◽  
Xiufen Zhou ◽  
Linquan Bai ◽  
...  

ABSTRACTThe pyrrole polyether antibiotic calcimycin (A23187) is a rare ionophore that is specific for divalent cations. It is widely used as a biochemical and pharmacological tool because of its multiple, unique biological effects. Here we report on the cloning, sequencing, and mutational analysis of the 64-kb biosynthetic gene cluster fromStreptomyces chartreusisNRRL 3882. Gene replacements confirmed the identity of the gene cluster, andin silicoanalysis of the DNA sequence revealed 27 potential genes, including 3 genes for the biosynthesis of the α-ketopyrrole moiety, 5 genes that encode modular type I polyketide synthases for the biosynthesis of the spiroketal ring, 4 genes for the biosynthesis of 3-hydroxyanthranilic acid, anN-methyltransferase tailoring gene, a resistance gene, a type II thioesterase gene, 3 regulatory genes, 4 genes with other functions, and 5 genes of unknown function. We propose a pathway for the biosynthesis of calcimycin and assign the genes to the biosynthesis steps. Our findings set the stage for producing much desired calcimycin derivatives using genetic modification instead of chemical synthesis.


2012 ◽  
Vol 56 (8) ◽  
pp. 4175-4183 ◽  
Author(s):  
Seung Young Kim ◽  
Kou-San Ju ◽  
William W. Metcalf ◽  
Bradley S. Evans ◽  
Tomohisa Kuzuyama ◽  
...  

ABSTRACTFosfomycin is a wide-spectrum antibiotic that is used clinically to treat acute cystitis in the United States. The compound is produced by several strains of streptomycetes and pseudomonads. We sequenced the biosynthetic gene cluster responsible for fosfomycin production inPseudomonas syringaePB-5123. Surprisingly, the biosynthetic pathway in this organism is very different from that inStreptomyces fradiaeandStreptomyces wedmorensis. The pathways share the first and last steps, involving conversion of phosphoenolpyruvate to phosphonopyruvate (PnPy) and 2-hydroxypropylphosphonate (2-HPP) to fosfomycin, respectively, but the enzymes converting PnPy to 2-HPP are different. The genome ofP. syringaePB-5123 lacks a gene encoding the PnPy decarboxylase found in theStreptomycesstrains. Instead, it contains a gene coding for a citrate synthase-like enzyme, Psf2, homologous to the proteins that add an acetyl group to PnPy in the biosynthesis of FR-900098 and phosphinothricin. Heterologous expression and purification of Psf2 followed by activity assays confirmed the proposed activity of Psf2. Furthermore, heterologous production of fosfomycin inPseudomonas aeruginosafrom a fosmid encoding the fosfomycin biosynthetic cluster fromP. syringaePB-5123 confirmed that the gene cluster is functional. Therefore, two different pathways have evolved to produce this highly potent antimicrobial agent.


2009 ◽  
Vol 192 (2) ◽  
pp. 426-435 ◽  
Author(s):  
Silke I. Patzer ◽  
Volkmar Braun

ABSTRACT The main siderophores produced by streptomycetes are desferrioxamines. Here we show that Streptomyces sp. ATCC 700974 and several Streptomyces griseus strains, in addition, synthesize a hitherto unknown siderophore with a catechol-peptide structure, named griseobactin. The production is repressed by iron. We sequenced a 26-kb DNA region comprising a siderophore biosynthetic gene cluster encoding proteins similar to DhbABCEFG, which are involved in the biosynthesis of 2,3-dihydroxybenzoate (DHBA) and in the incorporation of DHBA into siderophores via a nonribosomal peptide synthetase. Adjacent to the biosynthesis genes are genes that encode proteins for the secretion, uptake, and degradation of siderophores. To correlate the gene cluster with griseobactin synthesis, the dhb genes in ATCC 700974 were disrupted. The resulting mutants no longer synthesized DHBA and griseobactin; production of both was restored by complementation with the dhb genes. Heterologous expression of the dhb genes or of the entire griseobactin biosynthesis gene cluster in the catechol-negative strain Streptomyces lividans TK23 resulted in the synthesis and secretion of DHBA or griseobactin, respectively, suggesting that these genes are sufficient for DHBA and griseobactin biosynthesis. Griseobactin was purified and characterized; its structure is consistent with a cyclic and, to a lesser extent, linear form of the trimeric ester of 2,3-dihydroxybenzoyl-arginyl-threonine complexed with aluminum under iron-limiting conditions. This is the first report identifying the gene cluster for the biosynthesis of DHBA and a catechol siderophore in Streptomyces.


1997 ◽  
Vol 179 (14) ◽  
pp. 4464-4472 ◽  
Author(s):  
A Peñaloza-Vázquez ◽  
S P Kidambi ◽  
A M Chakrabarty ◽  
C L Bender

2010 ◽  
Vol 192 (21) ◽  
pp. 5688-5699 ◽  
Author(s):  
Roman Netzer ◽  
Marit H. Stafsnes ◽  
Trygve Andreassen ◽  
Audun Goksøyr ◽  
Per Bruheim ◽  
...  

ABSTRACT We report the cloning and characterization of the biosynthetic gene cluster (crtE, crtB, crtI, crtE2, crtYg, crtYh, and crtX) of the γ-cyclic C50 carotenoid sarcinaxanthin in Micrococcus luteus NCTC2665. Expression of the complete and partial gene cluster in Escherichia coli hosts revealed that sarcinaxanthin biosynthesis from the precursor molecule farnesyl pyrophosphate (FPP) proceeds via C40 lycopene, C45 nonaflavuxanthin, C50 flavuxanthin, and C50 sarcinaxanthin. Glucosylation of sarcinaxanthin was accomplished by the crtX gene product. This is the first report describing the biosynthetic pathway of a γ-cyclic C50 carotenoid. Expression of the corresponding genes from the marine M. luteus isolate Otnes7 in a lycopene-producing E. coli host resulted in the production of up to 2.5 mg/g cell dry weight sarcinaxanthin in shake flasks. In an attempt to experimentally understand the specific difference between the biosynthetic pathways of sarcinaxanthin and the structurally related ε-cyclic decaprenoxanthin, we constructed a hybrid gene cluster with the γ-cyclic C50 carotenoid cyclase genes crtYg and crtYh from M. luteus replaced with the analogous ε-cyclic C50 carotenoid cyclase genes crtYe and crtYf from the natural decaprenoxanthin producer Corynebacterium glutamicum. Surprisingly, expression of this hybrid gene cluster in an E. coli host resulted in accumulation of not only decaprenoxanthin, but also sarcinaxanthin and the asymmetric ε- and γ-cyclic C50 carotenoid sarprenoxanthin, described for the first time in this work. Together, these data contributed to new insight into the diverse and multiple functions of bacterial C50 carotenoid cyclases as key catalysts for the synthesis of structurally different carotenoids.


2008 ◽  
Vol 75 (4) ◽  
pp. 1144-1155 ◽  
Author(s):  
Brian M. Kevany ◽  
David A. Rasko ◽  
Michael G. Thomas

ABSTRACT Bacillus cereus UW85 produces the linear aminopolyol antibiotic zwittermicin A (ZmA). This antibiotic has diverse biological activities, such as suppression of disease in plants caused by protists, inhibition of fungal and bacterial growth, and amplification of the insecticidal activity of the toxin protein from Bacillus thuringiensis. ZmA has an unusual chemical structure that includes a d amino acid and ethanolamine and glycolyl moieties, as well as having an unusual terminal amide that is generated from the modification of the nonproteinogenic amino acid β-ureidoalanine. The diverse biological activities and unusual structure of ZmA have stimulated our efforts to understand how this antibiotic is biosynthesized. Here, we present the identification of the complete ZmA biosynthesis gene cluster from B. cereus UW85. A nearly identical gene cluster is identified on a plasmid from B. cereus AH1134, and we show that this strain is also capable of producing ZmA. Bioinformatics and biochemical analyses of the ZmA biosynthesis enzymes strongly suggest that ZmA is initially biosynthesized as part of a larger metabolite that is processed twice, resulting in the formation of ZmA and two additional metabolites. Additionally, we propose that the biosynthesis gene cluster for the production of the amino sugar kanosamine is contained within the ZmA biosynthesis gene cluster in B. cereus UW85.


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