Conformational analysis of the cyclic peptide rhizonin a in solution and crystalline state

Potgieter, M.; Steyn, Pieter S.; Heerden, Fanie R. van; Rooyen, Petrus H. van; Wessels, Philippus L.

doi:10.1016/s0040-4020(01)83435-9

Cited by 16 publications

(4 citation statements)

References 14 publications

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“…About two decades ago, the first mycotoxins from the Zygomycota, rhizonins A and B (1 and 2) (Fig. 1), were identified from a highly toxinogenic Rhizopus microsporus strain (MRC 303), which feasted on Mozambican groundnuts (15,19). In animal tests, the cyclic heptapeptides exhibit severe nonspecific hepatotoxicity; they cause a wide range of hepatic lesions and induce acute and chronic failure of the liver, which resulted in 100% lethality (23).…”

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confidence: 99%

Rhizonin, the First Mycotoxin Isolated from the Zygomycota, Is Not a Fungal Metabolite but Is Produced by Bacterial Endosymbionts

Partida‐Martínez

Looß

Ishida

et al. 2007

Appl Environ Microbiol

143

115

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Rhizonin is a hepatotoxic cyclopeptide isolated from cultures of a fungal Rhizopus microsporus strain that grew on moldy ground nuts in Mozambique. Reinvestigation of this fungal strain by a series of experiments unequivocally revealed that this "first mycotoxin from lower fungi" is actually not produced by the fungus. PCR experiments and phylogenetic studies based on 16S rRNA gene sequences revealed that the fungus is associated with bacteria belonging to the genus Burkholderia. By transmission electron microscopy, the bacteria were localized within the fungal cytosol. Toxin production and the presence of the endosymbionts were correlated by curing the fungus with an antibiotic, yielding a nonproducing, symbiont-free phenotype. The final evidence for a bacterial biogenesis of the toxin was obtained by the successful fermentation of the endosymbiotic bacteria in pure culture and isolation of rhizonin A from the broth. This finding is of particular interest since Rhizopus microsporus and related Rhizopus species are frequently used in food preparations such as tempeh and sufu.

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confidence: 99%

Rhizonin, the First Mycotoxin Isolated from the Zygomycota, Is Not a Fungal Metabolite but Is Produced by Bacterial Endosymbionts

Partida‐Martínez

Looß

Ishida

et al. 2007

Appl Environ Microbiol

143

115

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“…Interestingly, endolides incorporate a 3-(3-furyl)-alanine residue, a rare amino acid previously reported only twice. The first description corresponds to rhizonin A, a peptide described as produced by the zygomycete fungus Rhizopus microsporus [4,5], and later confirmed to be encoded by the symbiotic endobacterium Burkholderia endofungorum [6]. The second report of 3-(3-furyl)-alanine was associated with the cytotoxic bingchamides from Streptomyces bingchenggensis [7], reinforcing the hypothesis of a possible bacterial biosynthetic origin of this rare amino acid.…”

Section: Introductionmentioning

confidence: 71%

Time-Dependent Production of the Bioactive Peptides Endolides A and B and the Polyketide Mariline A from the Sponge-Derived Fungus Stachylidium bicolor 293K04

et al. 2017

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Previous investigations of the sponge-derived fungus Stachylidium bicolor (S. bicolor)293K04 led to the isolation of the biosynthetically unusual polyketides marilines A-C and the bioactive tetrapeptides endolides A-B, identified as potential neuropathic drug leads. Furthermore, prior extended solid cultivation of S. bicolor 293K04 for 60 days resulted in a significant increase of polyketide yield, and the isolation of seven new polyketides. Due to the interest in endolide activity, unusual biosynthetic diversity, and the late stage polyketide production, we studied the cultivation conditions for determining the production time distribution and yields of these secondary metabolites. Results indicated a first production phase of secondary metabolite dominated by peptides, after 21-23 days. Polyketide mariline A1/A2 only started at day 35 of growth, an unusually late period for secondary metabolite expression. This unusual bimodal sequential expression of different families of secondary metabolites suggests value in exploring extended cultivation times to identify novel bioactive fungal compounds.

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“…The methylamide proton typically came downfield of the acetamide proton in peptides 26 – 28 in chloroform; however, in the spectrum of pyrrolylalanine peptide 25 , the methylamide proton (5.93 ppm) was upfield relative to the signal for the acetamide proton (6.39 ppm). To distinguish the relative exposures of the amide protons to the solvent, the change in chemical shift of their signals was examined upon switching to a more polar solvent because in studies of cyclic and model linear peptides, polar solvents, which may form hydrogen bonds, cause the signals of exposed amide protons to downfield shift yet have limited influence on the chemical displacement of solvent-shielded protons. Downfield shifts of proton signals upon changes in solvent from chloroform to DMSO and water were significantly less for the methylamide (Δδ = 0.11–1.16 ppm) relative to the acetamide (Δδ = 1.82–2.04 ppm) for the trans -amide conformers of 26 – 28 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Protected 2-Pyrrolylalanine for Peptide Chemistry and Examination of Its Influence on Prolyl Amide Isomer Equilibrium

Dörr

Lubell

2012

J. Org. Chem.

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Protected enantiopure 2-pyrrolylalanine was synthesized for application in peptide science as an electron-rich arylalanine (histidine) analog with π-donor capability. (2S)-N-(Boc)-N'-(Phenylsulfonyl)-, (2S)-N,N'-bis-(phenylsulfonyl)-, and (2S)-N,N'-bis-(Boc)-3-(2-pyrrolyl)alanines (10, 3, and 14, respectively) were made in 13-17% overall yields and six to seven steps from oxazolidine β-methyl ester 4. Homoallylic ketone 5 was prepared by a copper-catalyzed cascade addition of vinylmagnesium bromide to ester 4 and converted to pyrrolyl amino alcohol 7 by olefin oxidation and Paal-Knorr condensation. Protecting group shuffle and oxidation of the primary alcohol enabled the synthesis of pyrrolylalanines. The bis-Boc analog 14 proved useful in peptide chemistry and was employed to make N-acetyl-pyrrolylalaninyl-proline N''-methylamide 25. A study of the influence of the pyrrole moiety on the prolyl amide isomer equilibrium of 25 using (1)H NMR spectroscopy in chloroform, DMSO, and water demonstrated that the pyrrolylalanine peptide exhibited behavior and conformations different from those of other arylalanine analogs.

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Conformational analysis of the cyclic peptide rhizonin a in solution and crystalline state

Cited by 16 publications

References 14 publications

Rhizonin, the First Mycotoxin Isolated from the Zygomycota, Is Not a Fungal Metabolite but Is Produced by Bacterial Endosymbionts

Rhizonin, the First Mycotoxin Isolated from the Zygomycota, Is Not a Fungal Metabolite but Is Produced by Bacterial Endosymbionts

Time-Dependent Production of the Bioactive Peptides Endolides A and B and the Polyketide Mariline A from the Sponge-Derived Fungus Stachylidium bicolor 293K04

Synthesis of Protected 2-Pyrrolylalanine for Peptide Chemistry and Examination of Its Influence on Prolyl Amide Isomer Equilibrium

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