Talaromyces
Dotaz
Zobrazit nápovědu
Fungal β-N-acetylhexosaminidases, though hydrolytic enzymes in vivo, are useful tools in the preparation of oligosaccharides of biological interest. The β-N-acetylhexosaminidase from Talaromyces flavus is remarkable in terms of its synthetic potential, broad substrate specificity, and tolerance to substrate modifications. It can be heterologously produced in Pichia pastoris in a high yield. The mutation of the Tyr470 residue to histidine greatly enhances its transglycosylation capability. The aim of this work was to identify the structural requirements of this model β-N-acetylhexosaminidase for its transglycosylation acceptors and formulate a structure-activity relationship study. Enzymatic reactions were performed using an activated glycosyl donor, 4-nitrophenyl N-acetyl-β-d-glucosaminide or 4-nitrophenyl N-acetyl-β-d-galactosaminide, and a panel of glycosyl acceptors of varying structural features (N-acetylglucosamine, glucose, N-acetylgalactosamine, galactose, N-acetylmuramic acid, and glucuronic acid). The transglycosylation products were isolated and structurally characterized. The C-2 N-acetamido group in the acceptor molecule was found to be essential for recognition by the enzyme. The presence of the C-2 hydroxyl moiety strongly hindered the normal course of transglycosylation, yielding unique non-reducing disaccharides in a low yield. Moreover, whereas the gluco-configuration at C-4 steered the glycosylation into the β(1-4) position, the galacto-acceptor afforded a β(1-6) glycosidic linkage. The Y470H mutant enzyme was tested with acceptors based on β-glycosides of uronic acid and N-acetylmuramic acid. With the latter acceptor, we were able to isolate and characterize one glycosylation product in a low yield. To our knowledge, this is the first example of enzymatic glycosylation of an N-acetylmuramic acid derivative. In order to explain these findings and predict enzyme behavior, a modeling study was accomplished that correlated with the acquired experimental data.
- MeSH
- beta-N-acetylhexosaminidasy chemie metabolismus MeSH
- glykosidy metabolismus MeSH
- glykosylace MeSH
- kinetika MeSH
- konformace proteinů MeSH
- molekulární modely MeSH
- oligosacharidy metabolismus MeSH
- substrátová specifita MeSH
- Talaromyces enzymologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
A filamentous fungus displaying high cellulase activity was isolated from a compost heap with triticale (a wheat-rye hybrid) as the main constituent. It was preliminarily identified as a Talaromyces pinophilus species. A 2577 base pair β-glucosidase gene was cloned from complementary DNA and heterologously expressed in Saccharomyces cerevisiae. The recombinant β-glucosidase production profile was assessed and compared to that of the Saccharomycopsis fibuligera β-glucosidase which served as a benchmark. The enzyme was also characterised in terms of pH and temperature tolerance as well as response to inhibitors. Maximal extracellular β-glucosidase activity of 0.56 nkat/mg total protein was measured using p-nitrophenyl-β-D-glucopyranoside as substrate. The recombinant protein displayed a pH optimum of 4.0, and good thermostability as 70% of maximal enzyme activity was retained after 1 h at 60 °C. Activity of the recombinant β-glucosidase was adversely affected by the presence of glucose and ethanol at higher concentrations while xylose had no effect. The expression of the T. pinophilus β-glucosidase did not reach the same titres as for the benchmark; however, in the context of constructing a yeast strain for bioethanol production in a consolidated bioprocess, the enzyme may still show good potential.
- MeSH
- ethanol metabolismus MeSH
- exprese genu * MeSH
- fenotyp MeSH
- fermentace MeSH
- genotyp MeSH
- glukosylceramidasa genetika metabolismus MeSH
- klonování DNA MeSH
- rekombinantní proteiny genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- Talaromyces enzymologie genetika MeSH
- Publikační typ
- časopisecké články MeSH
The present work is aimed to hypothesize that fungal endophytes associated with wheat (Triticum aestivum L.) plants can play a variety of roles in biotechnology including plant growth. Out of 67 fungal isolates, five maximum drought-tolerant isolates were used to check their various plant growth-promoting traits, antioxidants, and antifungal activities under secondary screening. Fungal isolate #8TAKS-3a exhibited the maximum drought tolerance capacity and potential to produce auxin, gibberellic acid, ACC deaminase, phosphate, zinc solubilization, ammonia, siderophore, and extracellular enzyme activities followed by #6TAKR-1a isolate. In terms of antioxidant activities, #8TAKS-3a culture also showed maximum DPPH scavenging, total antioxidant, and NO-scavenging activities. However, #6TAKR-1a exhibited maximum total flavonoid content, total phenolic content, and Fe-reducing power and also the highest growth inhibition of Aspergillus niger (ITCC 6152) and Colletotrichum sp. (ITCC 6152). Based on morphological characters and multi-locus phylogenetic analysis of the nuc rDNA internal transcribed spacer region (ITS1-5.8S-ITS2 = ITS), β-tubulin (TUB 2), and RNA polymerase II second largest subunit (RPB2) genes, potent fungal isolate #8TAKS-3a was identified as Talaromyces purpureogenus. Under the in vitro conditions, T. purpureogenus (#8TAKS-3a) was used as a bioinoculant that displayed a significant increase in various physio-biochemical growth parameters under normal and stressed conditions (p < 0.05). Our results indicate that drought stress-tolerant T. purpureogenus can be further used for field testing as a growth promoter.
- MeSH
- antioxidancia MeSH
- endofyty MeSH
- fylogeneze MeSH
- období sucha MeSH
- pšenice MeSH
- semenáček * MeSH
- Talaromyces * genetika MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- aminokyseliny MeSH
- houby metabolismus ultrastruktura MeSH
- lipidy MeSH
- Penicillium metabolismus ultrastruktura MeSH
- proteiny MeSH
- Publikační typ
- srovnávací studie MeSH
BACKGROUND: β-N-Acetylhexosaminidase (GH20) from the filamentous fungus Talaromyces flavus, previously identified as a prominent enzyme in the biosynthesis of modified glycosides, lacks a high resolution three-dimensional structure so far. Despite of high sequence identity to previously reported Aspergillus oryzae and Penicilluim oxalicum β-N-acetylhexosaminidases, this enzyme tolerates significantly better substrate modification. Understanding of key structural features, prediction of effective mutants and potential substrate characteristics prior to their synthesis are of general interest. RESULTS: Computational methods including homology modeling and molecular dynamics simulations were applied to shad light on the structure-activity relationship in the enzyme. Primary sequence analysis revealed some variable regions able to influence difference in substrate affinity of hexosaminidases. Moreover, docking in combination with consequent molecular dynamics simulations of C-6 modified glycosides enabled us to identify the structural features required for accommodation and processing of these bulky substrates in the active site of hexosaminidase from T. flavus. To access the reliability of predictions on basis of the reported model, all results were confronted with available experimental data that demonstrated the principal correctness of the predictions as well as the model. CONCLUSIONS: The main variable regions in β-N-acetylhexosaminidases determining difference in modified substrate affinity are located close to the active site entrance and engage two loops. Differences in primary sequence and the spatial arrangement of these loops and their interplay with active site amino acids, reflected by interaction energies and dynamics, account for the different catalytic activity and substrate specificity of the various fungal and bacterial β-N-acetylhexosaminidases.
- MeSH
- beta-N-acetylhexosaminidasy chemie metabolismus MeSH
- fylogeneze MeSH
- glykosylace MeSH
- katalytická doména MeSH
- kinetika MeSH
- molekulární modely MeSH
- molekulární sekvence - údaje MeSH
- reprodukovatelnost výsledků MeSH
- sekvence aminokyselin MeSH
- sekvenční homologie aminokyselin MeSH
- simulace molekulární dynamiky MeSH
- substrátová specifita MeSH
- Talaromyces enzymologie MeSH
- výpočetní biologie * MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
It is known that intracellular pathogens interact and react with the cellular immune system through exosomes produced by macrophages. This study aimed to determine whether co-culture of macrophages and Talaromyces marneffei induces exosomes and leads to immune responses. T. marneffei was incubated to collect conidia, co-cultured with human macrophages, which then induced exosomes. In cellular experiments, after extraction and purification, the exosomes were then observed by electron microscopy and detected by flow cytometry and mass spectrometry. In animal experiments, flow cytometry and enzyme-linked immunosorbent assay were used to examine whether exosomes were antigenpresenting. The results showed that purified exosomes produced a pro-inflammatory response and stimulated production of TNF-α in non-fungal-treated macrophages. Protein mass spectrometry analysis of exosomes also indicated their potential ability to activate the internal immune response system and the pro-inflammatory response. Translation and ribosomes were the most abundant GO terms in proteins, and the most relevant KEGG pathway was the biosynthesis of secondary metabolites. Furthermore, in vivo experiments revealed that exosomes induced activation of lymphocytes and increased expression of TNF-α and IL-12 in the lung, mediastinum, and spleen area. In conclusion, exosomes can be released by co-culture of T. marneffei and macrophages, having antigen-presenting functions, promoting macrophage inflammation, and initiating adaptive immune responses. These processes are inextricably linked to the translation of secondary metabolites, ribosomes and biosynthesis.
Bioethanol production from lignocellulosic materials is hindered by the high costs of pretreatment and the enzymes. The present study aimed to evaluate whether co-cultivation of four selected cellulolytic fungi yields higher cellulase and xylanase activities compared to the monocultures and to investigate whether the enzymes from the co-cultures yield higher saccharification on selected plant materials without thermo-chemical pretreatment. The fungal isolates, Trichoderma reesei F118, Penicillium javanicum FS7, Talaromyces sp. F113, and Talaromyces pinophilus FM9, were grown as monocultures and binary co-cultures under submerged conditions for 7 days. The cellulase and xylanase activities of the culture filtrates were measured, and the culture filtrates were employed for the saccharification of sugarcane leaves, Guinea grass leaves, and water hyacinth stems and leaves. Total reducing sugars and individual sugars released from each plant material were quantified. The co-culture of Talaromyces sp. F113 with Penicillium javanicum FS7 and of T. reesei F118 with T. pinophilus FM9 produced significantly higher cellulase activities compared to the corresponding monocultures whereas no effect was observed on xylanase activities. Overall, the highest amounts of total reducing sugars and individual sugars were obtained from Guinea grass leaves saccharified with the co-culture of T. reesei F118 with T. pinophilus FM9, yielding 63.5% saccharification. Guinea grass leaves were found to be the most susceptible to enzymatic saccharification without pre-treatment, while water hyacinth stems and leaves were the least. Accordingly, the study suggests that fungal co-cultivation could be a promising approach for the saccharification of lignocellulosic materials for bioethanol production.
- MeSH
- celulasa * metabolismus MeSH
- endo-1,4-beta-xylanasy metabolismus MeSH
- ethanol metabolismus MeSH
- Hypocreales enzymologie metabolismus růst a vývoj MeSH
- kokultivační techniky * MeSH
- lignin * metabolismus MeSH
- listy rostlin mikrobiologie MeSH
- Penicillium * enzymologie metabolismus růst a vývoj MeSH
- Saccharum * mikrobiologie metabolismus MeSH
- Talaromyces * enzymologie metabolismus růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
The β-N-acetylhexosaminidase from Talaromyces flavus has a remarkable synthetic ability, processing even carbohydrates with various functionalities. Its broader use is partially hampered by low-yield production in the native fungus. Here, we present an optimized 3-day production of this enzyme in the eukaryotic host of Pichia pastoris, in ca 10-fold higher volume activity (10 U/ml) and close-to-perfect purity (one chromatographic step needed). Importantly, the recombinant enzyme features the same biochemical and catalytic properties, including the syntheses with derivatized carbohydrate substrates. This is the first example of the overexpression of a fungal β-N-acetylhexosaminidase by a single-cell producer in liquid medium. It represents a promising solution for wider biotechnological applications of this outstanding enzyme.
- MeSH
- beta-N-acetylhexosaminidasy genetika izolace a purifikace MeSH
- exprese genu MeSH
- klonování DNA MeSH
- komplementární DNA genetika MeSH
- Pichia genetika MeSH
- rekombinantní proteiny genetika izolace a purifikace MeSH
- sekvenční analýza DNA MeSH
- Talaromyces enzymologie genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
