Topic
Agrocybe
About: Agrocybe is a research topic. Over the lifetime, 240 publications have been published within this topic receiving 3302 citations.
Papers published on a yearly basis
Papers
TL;DR: Agrocybe aegerita, a bark mulch- and wood-colonizing basidiomycete, was found to produce a peroxidase (AaP) that oxidizes aryl alcohols into the corresponding aldehydes and then into benzoic acids, consistent with the fact that AaP halogenates monochlorodimedone, the specific substrate of CPO.
Abstract: Agrocybe aegerita, a bark mulch- and wood-colonizing basidiomycete, was found to produce a peroxidase (AaP) that oxidizes aryl alcohols, such as veratryl and benzyl alcohols, into the corresponding aldehydes and then into benzoic acids. The enzyme also catalyzed the oxidation of typical peroxidase substrates, such as 2,6-dimethoxyphenol (DMP) or 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS). A. aegerita peroxidase production depended on the concentration of organic nitrogen in the medium, and highest enzyme levels were detected in the presence of soybean meal. Two fractions of the enzyme, AaP I and AaP II, which had identical molecular masses (46 kDa) and isoelectric points of 4.6 to 5.4 and 4.9 to 5.6, respectively (corresponding to six different isoforms), were identified after several steps of purification, including anion- and cation-exchange chromatography. The optimum pH for the oxidation of aryl alcohols was found to be around 7, and the enzyme required relatively high concentrations of H2O2 (2 mM) for optimum activity. The apparent Km values for ABTS, DMP, benzyl alcohol, veratryl alcohol, and H2O2 were 37, 298, 1,001, 2,367 and 1,313 μM, respectively. The N-terminal amino acid sequences of the main AaP II spots blotted after two-dimensional gel electrophoresis were almost identical and exhibited almost no homology to the sequences of other peroxidases from basidiomycetes, but they shared the first three amino acids, as well as two additional amino acids, with the heme chloroperoxidase (CPO) from the ascomycete Caldariomyces fumago. This finding is consistent with the fact that AaP halogenates monochlorodimedone, the specific substrate of CPO. The existence of haloperoxidases in basidiomycetous fungi may be of general significance for the natural formation of chlorinated organic compounds in forest soils.
347 citations
TL;DR: A second fungal haloperoxidase of the heme-thiolate type has been discovered in the agaric mushroom Agrocybe aegerita and could become promising biocatalysts in biotechnological applications because they seemingly fill the gap between CPO and P450 enzymes and act as “self-sufficient” peroxygenases.
Abstract: Heme-thiolate haloperoxidases are undoubtedly the most versatile biocatalysts of the hemeprotein family and share catalytic properties with at least three further classes of heme-containing oxidoreductases, namely, classic plant and fungal peroxidases, cytochrome P450 monooxygenases, and catalases. For a long time, only one enzyme of this type--the chloroperoxidase (CPO) of the ascomycete Caldariomyces fumago--has been known. The enzyme is commercially available as a fine chemical and catalyzes the unspecific chlorination, bromination, and iodation (but no fluorination) of a variety of electrophilic organic substrates via hypohalous acid as actual halogenating agent. In the absence of halide, CPO resembles cytochrome P450s and epoxidizes and hydroxylates activated substrates such as organic sulfides and olefins; aromatic rings, however, are not susceptible to CPO-catalyzed oxygen-transfer. Recently, a second fungal haloperoxidase of the heme-thiolate type has been discovered in the agaric mushroom Agrocybe aegerita. The UV-Vis adsorption spectrum of the isolated enzyme shows little similarity to that of CPO but is almost identical to a resting-state P450. The Agrocybe aegerita peroxidase (AaP) has strong brominating as well as weak chlorinating and iodating activities, and catalyzes both benzylic and aromatic hydroxylations (e.g., of toluene and naphthalene). AaP and related fungal peroxidases could become promising biocatalysts in biotechnological applications because they seemingly fill the gap between CPO and P450 enzymes and act as "self-sufficient" peroxygenases. From the environmental point of view, the existence of a halogenating mushroom enzyme is interesting because it could be linked to the multitude of halogenated compounds known from these organisms.
259 citations
TL;DR: The directed-evolution platform described is a valuable point of departure for the development of customized UPOs with improved features and for the study of structure-function relationships.
Abstract: Unspecific peroxygenase (UPO) represents a new type of heme-thiolate enzyme with self-sufficient mono(per)oxygenase activity and many potential applications in organic synthesis. With a view to taking advantage of these properties, we subjected the Agrocybe aegerita UPO1-encoding gene to directed evolution in Saccharomyces cerevisiae. To promote functional expression, several different signal peptides were fused to the mature protein, and the resulting products were tested. Over 9,000 clones were screened using an ad hoc dual-colorimetric assay that assessed both peroxidative and oxygen transfer activities. After 5 generations of directed evolution combined with hybrid approaches, 9 mutations were introduced that resulted in a 3,250-fold total activity improvement with no alteration in protein stability. A breakdown between secretion and catalytic activity was performed by replacing the native signal peptide of the original parental type with that of the evolved mutant; the evolved leader increased functional expression 27-fold, whereas an 18-fold improvement in the kcat/Km value for oxygen transfer activity was obtained. The evolved UPO1 was active and highly stable in the presence of organic cosolvents. Mutations in the hydrophobic core of the signal peptide contributed to enhance functional expression up to 8 mg/liter, while catalytic efficiencies for peroxidative and oxygen transfer reactions were increased by several mutations in the vicinity of the heme access channel. Overall, the directed-evolution platform described is a valuable point of departure for the development of customized UPOs with improved features and for the study of structure-function relationships.
210 citations
TL;DR: An antitumour lectin consisting of two identical subunits of 15.8 kDa was isolated from the fruiting bodies of the edible mushroom Agrocybe aegerita and showed strong inhibition of the growth of human tumour cell lines HeLa, SW480, SGC-7901, MGC80-3, BGC-823, HL-60 and mouse sarcoma S-180.
Abstract: An antitumour lectin (named AAL) consisting of two identical subunits of 15.8 kDa was isolated from the fruiting bodies of the edible mushroom Agrocybe aegerita using a procedure which involved precipitating the extract by addition of (NH(4))(2)SO(4), ion exchange chromatography on DEAE-Sepharose Fast Flow, gel filtration chromatography on Sephacryl S-200 HR and finally purification on a GF-250 HPLC column. Amino acid analysis of the N-terminus and an internal fragment indicated that the sequences of the two fragments were QGVNIYNI and Q(K)PDGPWLVEK(Q)R respectively. AAL showed strong inhibition of the growth of human tumour cell lines HeLa, SW480, SGC-7901, MGC80-3, BGC-823, HL-60 and mouse sarcoma S-180. AAL also inhibited the viability of S-180 tumour cells in vivo. Analysis by Hoechst 33258 staining, MitoSensor Kit and flow cytometry showed that AAL induced apoptosis in HeLa cells. TUNEL (terminal transferase deoxytidyl uridine end labelling) analysis of slides of tumour tissues excised from BALB/c mice also demonstrated the apoptosis-induction activity of the lectin. Furthermore, AAL was shown to possess DNase activity in assays using plasmid pCDNA3 and salmon sperm DNA. Based on the results obtained in these assays, we conclude that AAL exerts its antitumour effects via apoptosis-inducing and DNase activities.
146 citations
TL;DR: In many cases, the product patterns of UPOs resemble those of human cytochrome P450 (P450) monooxygenases and, in fact, combine the catalytic cycle of heme peroxidases with the "peroxide shunt" of P450s.
Abstract: Eleven years ago, a secreted heme-thiolate peroxidase with promiscuity for oxygen transfer reactions was discovered in the basidiomycetous fungus, Agrocybe aegerita. The enzyme turned out to be a functional mono-peroxygenase that transferred an oxygen atom from hydrogen peroxide to diverse organic substrates (aromatics, heterocycles, linear and cyclic alkanes/alkenes, fatty acids, etc.). Later similar enzymes were found in other mushroom genera such as Coprinellus and Marasmius. Approximately one thousand putative peroxygenase sequences that form two large clusters can be found in genetic databases and fungal genomes, indicating the widespread occurrence of such enzymes in the whole fungal kingdom including all phyla of true fungi (Eumycota) and certain fungus-like heterokonts (Oomycota). This new enzyme type was classified as unspecific peroxygenase (UPO, EC 1.11.2.1) and placed in a separate peroxidase subclass. Furthermore, UPOs and related heme-thiolate peroxidases such as well-studied chloroperoxidase (CPO) represent a separate superfamily of heme proteins on the phylogenetic level. The reactions catalyzed by UPOs include hydroxylation, epoxidation, O- and N-dealkylation, aromatization, sulfoxidation, N-oxygenation, dechlorination and halide oxidation. In many cases, the product patterns of UPOs resemble those of human cytochrome P450 (P450) monooxygenases and, in fact, combine the catalytic cycle of heme peroxidases with the “peroxide shunt” of P450s. Here, an overview on UPOs is provided with focus on their molecular and catalytic properties.
142 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 4 |
| 2020 | 11 |
| 2019 | 16 |
| 2018 | 18 |
| 2017 | 16 |
| 2016 | 18 |