Three Redundant Synthetases Secure Redox-Active Pigment Production in the Basidiomycete Paxillus involutus

Braesel, Jana; Götze, Sebastian; Shah, Firoz; Heine, Daniel; Tauber, James P.; Hertweck, Christian; Tunlid, Anders; Stallforth, Pierre; Hoffmeister, Dirk

doi:10.1016/j.chembiol.2015.08.016

Cited by 46 publications

(51 citation statements)

References 36 publications

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“…Owing to the large difficulties in measuring ˙ OH production in complex systems like soils, the activity of this process might be inferred from analyzing the expression levels of genes encoding enzymes involved in synthesizing the Fenton chemistry reactants. We have previously identified synthetases that are involved in the biosynthesis of the Fe 3+ ‐reductant involutin (Braesel et al ., ). Knowing the precise nutritional signals that regulate the induction of ˙ OH production opens up new possibilities for characterizing the molecular components of the Fenton‐based protein degradation mechanism in ECM fungi.…”

Section: Discussionmentioning

confidence: 99%

Fenton reaction facilitates organic nitrogen acquisition by an ectomycorrhizal fungus

et al. 2018

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Summary Boreal trees rely on their ectomycorrhizal fungal symbionts to acquire growth‐limiting nutrients, such as nitrogen (N), which mainly occurs as proteins complexed in soil organic matter (SOM). The mechanisms for liberating this N are unclear as ectomycorrhizal fungi have lost many genes encoding lignocellulose‐degrading enzymes present in their saprotrophic ancestors. We hypothesized that hydroxyl radicals (˙ OH), produced by the ectomycorrhizal fungus Paxillus involutus during growth on SOM, are involved in liberating organic N. Paxillus involutus was grown for 7 d on N‐containing or N‐free substrates that represent major organic compounds of SOM. ˙ OH production, ammonium assimilation, and proteolytic activity were measured daily. ˙ OH production was strongly induced when P. involutus switched from ammonium to protein as the main N source. Extracellular proteolytic activity was initiated shortly after the oxidation. Oxidized protein substrates induced higher proteolytic activity than unmodified proteins. Dynamic modeling predicted that ˙ OH production occurs in a burst, regulated mainly by ammonium and ferric iron concentrations.We propose that the production of ˙ OH and extracellular proteolytic enzymes are regulated by similar nutritional signals. Oxidation works in concert with proteolysis, improving N liberation from proteins in SOM. Organic N mining by ectomycorrhizal fungi has, until now, only been attributed to proteolysis.

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Section: Discussionmentioning

confidence: 99%

Fenton reaction facilitates organic nitrogen acquisition by an ectomycorrhizal fungus

et al. 2018

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“…This inducing agent(s) may trigger a stress specific response in S. lacrymans , but may even be part of a more generic response mechanism. The atromentin‐derived pigments were shown here to not have antimicrobial activity and they are also heavily present from a nutritional cue and involved in redox cycling for lignocellulose breakdown (Eastwood et al ., ; Braesel et al ., ). Thus, this mechanism may overlap with a nutritional response and as such may be co‐regulated alongside many other cellular processes including stress, nutrition and secondary metabolism.…”

Section: Discussionmentioning

confidence: 99%

Bacteria induce pigment formation in the basidiomyceteSerpula lacrymans

Tauber

Schroeckh

Shelest

et al. 2016

Environmental Microbiology

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Basidiomycete fungi are characterized ecologically for their vital functional role in ecosystem carbon recycling and chemically for their capacity to produce a diverse array of small molecules. Chromophoric natural products derived from the quinone precursor atromentin, such as variegatic acid and involutin, have been shown to function in redox cycling. Yet, in the context of an inter-kingdom natural system these pigments are still elusive. Here, we co-cultured the model saprotrophic basidiomycete Serpula lacrymans with an ubiquitous terrestrial bacterium, either Bacillus subtilis, Pseudomonas putida, or Streptomyces iranensis. For each, there was induction of the gene cluster encoding a non-ribosomal peptide synthetase-like enzyme (atromentin synthetase) and an aminotransferase which together produce atromentin. Correspondingly, during co-culturing there was an increase in secreted atromentin-derived pigments, i.e., variegatic, xerocomic, isoxerocomic, and atromentic acid. Bioinformatic analyses from 14 quinone synthetase genes, twelve of which are encoded in a cluster, identified a common promoter motif indicating a general regulatory mechanism for numerous basidiomycetes.

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“…Several fungal NRPSs contain thioesterase domains that catalyze the condensation of two β-ketoacids that subsequently cyclize to form furanone cores of several pigment molecules. 41, 42 The thioesterase domains have also been implicated in the Dieckmann cyclization in bacterial tetramate natural products 43, 44 as well as β-lactam formation in the production of sulfazecin. 45 Although not quite as chemically diverse as the chemical reactions catalyzed above, adenylation domains also have been observed to catalyze unexpected reactions.…”

Section: The Biochemistry and Structural Biology Of The Nonribosommentioning

confidence: 99%

Nonribosomal peptide synthetase biosynthetic clusters of ESKAPE pathogens

Gulick

2017

Nat. Prod. Rep.

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Overview Natural products are important secondary metabolites produced by bacterial and fungal species that play important roles in cellular growth and signaling, nutrient acquisition, intra- and interspecies communication, and virulence. A subset of natural products is produced by nonribosomal peptide synthetases (NRPSs), a family of large, modular enzymes that function in an assembly line fashion. Because of the pharmaceutical activity of many NRPS products, much effort has gone into the exploration of their biosynthetic pathways and the diverse products they make. Many interesting NRPS pathways have been identified and characterized from both terrestrial and marine bacterial sources. Recently, several NRPS pathways in human commensal bacterial species have been identified that produce molecules with antibiotic activity, suggesting another source of interesting NRPS pathways may be the commensal and pathogenic bacteria that live on the human body. The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) have been identified as a significant cause of human bacterial infections that are frequently multidrug resistant. The emerging resistance profile of these organisms has prompted calls from multiple international agencies to identify novel antibacterial targets and develop new approaches to treat infections from ESKAPE pathogens. Each of these species contains several NRPS biosynthetic gene clusters. While some have been well characterized and produce known natural products with important biological roles in microbial physiology, others have yet to be investigated. This review catalogs the NRPS pathways of ESKAPE pathogens. The exploration of novel NRPS products may lead to a better understanding of the chemical communication used by human pathogens and potentially to the discovery of novel therapeutic approaches.

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Three Redundant Synthetases Secure Redox-Active Pigment Production in the Basidiomycete Paxillus involutus

Cited by 46 publications

References 36 publications

Fenton reaction facilitates organic nitrogen acquisition by an ectomycorrhizal fungus

Fenton reaction facilitates organic nitrogen acquisition by an ectomycorrhizal fungus

Bacteria induce pigment formation in the basidiomyceteSerpula lacrymans

Nonribosomal peptide synthetase biosynthetic clusters of ESKAPE pathogens

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