Peptide Synthesis without Ribosomes

Walton, Jonathan D.; Panaccione, Daniel G.; Hallen, Heather E.

doi:10.1007/978-1-4419-8859-1_7

Cited by 22 publications

(13 citation statements)

References 164 publications

(162 reference statements)

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“…First, the animal peptides are not cyclized by peptide bonds, but acquire their essential rigidity by extensive disulfide bonds. Second, although ribosomally synthesized cyclic peptides have been described for bacteria, plants, and animals (e.g., the cyclotides and microcin J25) (26,27), to the best of our knowledge, all previously known fungal cyclic peptides are synthesized by nonribosomal peptide synthetases (14,15). Third, the Amanita toxins are not secreted (3), and, consistent with this fact, they lack predicted signal peptides (Figs.…”

Section: Resultsmentioning

confidence: 92%

“…2 A), was shotgun-sequenced to approximately two times the coverage of the genome (Ϸ70 MB total based on the known size of other homobasidiomycetes) (12) by a combination of automated Sanger sequencing and pyrosequencing (13). Because all known fungal cyclic peptides are biosynthesized by nonribosomal peptide synthetases (NRPSs) (14,15), the genome survey sequences were first queried with known bacterial and fungal NRPSs. No evidence for any NRPS was found in A. bisporigera; the most closely related sequences were orthologs of aminoadipate reductase and acyl-CoA synthase, which are other members of the aminoacyl-adenylating superfamily (15).…”

Section: Resultsmentioning

confidence: 99%

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Gene family encoding the major toxins of lethal Amanita mushrooms

Hallen

Luo

Scott-Craig

et al. 2007

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

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Amatoxins, the lethal constituents of poisonous mushrooms in the genus Amanita, are bicyclic octapeptides. Two genes in A. bisporigera, AMA1 and PHA1, directly encode ␣-amanitin, an amatoxin, and the related bicyclic heptapeptide phallacidin, a phallotoxin, indicating that these compounds are synthesized on ribosomes and not by nonribosomal peptide synthetases. ␣-Amanitin and phallacidin are synthesized as proproteins of 35 and 34 amino acids, respectively, from which they are predicted to be cleaved by a prolyl oligopeptidase. AMA1 and PHA1 are present in other toxic species of Amanita section Phalloidae but are absent from nontoxic species in other sections. The genomes of A. bisporigera and A. phalloides contain multiple sequences related to AMA1 and PHA1. The predicted protein products of this family of genes are characterized by a hypervariable ''toxin'' region capable of encoding a wide variety of peptides of 7-10 amino acids flanked by conserved sequences. Our results suggest that these fungi have a broad capacity to synthesize cyclic peptides on ribosomes.amanitin ͉ cyclic peptide ͉ phalloidin ͉ phallotoxin ͉ amatoxin

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Gene family encoding the major toxins of lethal Amanita mushrooms

Hallen

Luo

Scott-Craig

et al. 2007

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

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200

246

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“…LpsB is unusual among fungal NRPSs in that it forms a multienzyme complex with LpsA (42). Multienzyme NRPSs are common in prokaryotes, but the LpsA/LpsB system is the only described example in the fungal kingdom, where NRPSs are otherwise found on a single large multimodular polypeptide (55). There is a condensation domain found at the carboxy end of the LpsB protein and also a partial condensation domain at the aminoproximal end of the predicted N. lolii, but not C. purpurea, LpsA enzyme (20).…”

Section: Discussionmentioning

confidence: 99%

A Complex Ergovaline Gene Cluster in Epichloë Endophytes of Grasses

Fleetwood

Scott

Lane

et al. 2007

Appl Environ Microbiol

128

127

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Clavicipitaceous fungal endophytes of the genera Epichloë and Neotyphodium form symbioses with grasses of the subfamily Pooideae, in which they can synthesize an array of bioprotective alkaloids. Some strains produce the ergopeptine alkaloid ergovaline, which is implicated in livestock toxicoses caused by ingestion of endophyteinfected grasses. Cloning and analysis of a nonribosomal peptide synthetase (NRPS) gene from Neotyphodium lolii revealed a putative gene cluster for ergovaline biosynthesis containing a single-module NRPS gene, lpsB, and other genes orthologous to genes in the ergopeptine gene cluster of Claviceps purpurea and the clavine cluster of Aspergillus fumigatus. Despite conservation of gene sequence, gene order is substantially different between the N. lolii, C. purpurea, and A. fumigatus ergot alkaloid gene clusters. Southern analysis indicated that the N. lolii cluster was linked with previously identified ergovaline biosynthetic genes dmaW and lpsA. The ergovaline genes are closely associated with transposon relics, including retrotransposons and autonomous and nonautonomous DNA transposons. All genes in the cluster were highly expressed in planta, but expression was very low or undetectable in mycelia from axenic culture. This work provides a genetic foundation for elucidating biochemical steps in the ergovaline pathway, the ecological role of individual ergot alkaloid compounds, and the regulation of their synthesis in planta.

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“…Many plant-pathogenic fungi produce phytotoxins such as HCtoxin, victorin, sirodesmin PL, ergotamine and AM-toxin, by the activity of polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs). These phytotoxins act as virulence factors (Walton et al, 2004;Hoffmeister & Keller, 2007;Walton, 2006;Johnson et al, 2000;Elliott et al, 2007). Additionally, a PKS/NRPS hybrid enzyme (Ace1) of Magnaporthe grisea acts as an avirulence factor, triggering resistance in selective rice cultivars harbouring the corresponding resistance gene Pi33 (Böhnert et al, 2004;Collemare et al, 2008a, b;Fudal et al, 2007;Khaldi et al, 2008;Vergne et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Functional analysis of non-ribosomal peptide synthetases (NRPSs) in Trichoderma virens reveals a polyketide synthase (PKS)/NRPS hybrid enzyme involved in the induced systemic resistance response in maize

et al. 2012

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Trichoderma virens genome harbours genes encoding 22 non-ribosomal peptide synthetases (NRPSs) with at least one complete module (containing adenylation, thiolation and condensation domains) and four PKS/NRPS (polyketide synthase/NRPS) hybrid enzymes. After a primary screen for expression of these 26 genes when mycelia of T. virens are in contact with maize roots, seven genes that are upregulated were selected for further study. Using homologous recombination, loss-of-function mutants in six of these were obtained (the seventh, tex2, was acquired from our previous studies). Plant assays in a hydroponics system revealed that all seven mutants retained the ability to internally colonize maize roots. However, a mutation in one of the PKS/NRPS hybrid genes impaired the ability of T. virens to induce the defence response gene pal (phenylalanine ammonia lyase), suggesting a putative role for the associated metabolite product in induced systemic resistance. Interestingly, the mutant retained its ability to induce another defence response gene aos (allene oxide synthase). We thus provide evidence that a PKS/NRPS hybrid enzyme is involved in Trichoderma-plant interactions resulting in induction of defence responses.

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Peptide Synthesis without Ribosomes

Cited by 22 publications

References 164 publications

Gene family encoding the major toxins of lethal Amanita mushrooms

Gene family encoding the major toxins of lethal Amanita mushrooms

A Complex Ergovaline Gene Cluster in Epichloë Endophytes of Grasses

Functional analysis of non-ribosomal peptide synthetases (NRPSs) in Trichoderma virens reveals a polyketide synthase (PKS)/NRPS hybrid enzyme involved in the induced systemic resistance response in maize

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