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At least 19 recordsLinked to original sources
PubMed1992

Comparison of structure and activities of peroxidases from Coprinus cinereus, Coprinus macrorhizus and Arthromyces ramosus.

Initial structural and kinetic data suggested that peroxidases from Coprinus cinereus, Coprinus macrorhizus and Arthromyces ramosus were similar. Therefore they were characterized more fully. The three peroxidases were purified to RZ 2.5 and showed immunochemical identity as well as an identical M(r) of 38,000, pI about 3.5 and similar amino acid compositions. The N-termini were blocked for amino acid sequencing. The peroxidases had similar retention volumes by anion-exchange and gel-filtration chromatography. All peroxidases showed multiple peaks by Concanavalin A-Sepharose chromatography. The Concanavalin A-Sepharose profiles were different and depended furthermore on a fermentation batch. Tryptic peptide maps were very similar except for one peptide. This peptide contained an N-linked glycan composed of varying ratios of glucosamine and mannose for the three peroxidases. Rate constants and their pH dependence were the same for the three peroxidases using guaiacol or iodide as reducing substrates. We conclude that peroxidases from Coprinus cinereus, Coprinus macrorhizus and Arthromyces ramosus are most likely identical in their amino acid sequences, but deviate in glycosylation which, apparently, has no influence on the reaction rates of the enzyme. We suggest, that the Coprinus fungi express one peroxidase only in contrast to the lignin-degrading white-rot Basidiomycetes, which produce multiple peroxidase isozymes.

Amino Acid Sequence↗
PubMed1986

Analysis of the mitochondrial and nuclear genomes of two basidiomycetes, Coprinus cinereus and Coprinus stercorarius.

The mitochondrial and nuclear genomes of Coprinus stercorarius and C. cinereus were compared to assess their evolutionary relatedness and to characterize at the molecular level changes that have occurred since they diverged from a common ancestor. The mitochondrial genome of C. stercorarius (91.1 kb) is approximately twice as large as that of C. cinereus (43.3 kb). The pattern of restriction enzyme recognition sites shows both genomes to be circular, but reveals no clear homologies; furthermore, the order of structural genes is different in each species. The C. stercorarius mitochondrial genome contains a region homologous to a probe derived from the yeast mitochondrial var1 gene, whereas its nuclear genome does not. By contrast, the C. cinereus nuclear, but not mitochondrial, genome contains a region homologous to the var1 probe. Only a small fraction of either the nuclear or mitochondrial genomes, perhaps corresponding to the coding sequences, is capable of forming duplexes in interspecies solution reassociations, as measured by binding to hydroxylapatite. Those sequences capable of reassociating were found to have approximately 15% divergence for the mitochondrial genomes and 7%-15% divergence for the nuclear genomes, depending on the conditions of reassociation.

Basidiomycota↗
PubMed1987

Inversion of 5S ribosomal RNA genes within the genus Coprinus.

In the basidiomycete fungus Coprinus cinereus, the 5S ribosomal RNA (rRNA) genes are found in the rDNA repeat which encodes the other three rRNAs (18S, 5.8S, and 26S), and all genes are transcribed in the same direction (Cassidy et al. 1984). To facilitate examination of the rRNA gene organization in additional species, we developed a method to permit determination of the direction of transcription of the rRNA genes using crude preparations of genomic DNA. We used this method to determine the organization of the rDNA in five other members of the order Agaricales (Flammulina velutipes, Agaricus bisporus, Coprinus micaceus, Coprinus atramentarius, and Coprinus comatus). In four, the organization is the same as it is in Coprinus cinereus. However, in Coprinus comatus, the 5S RNA gene is present in the rDNA repeat, but is transcribed in the opposite direction. This alteration in rDNA organization within the genus Coprinus indicates that inverted 5S genes can arise and become propagated through the tandem array of genes. The presence of orientation-dependent promoter elements within the spacer DNA (Elion and Warner 1984) would be expected to place constraints on such inversions.

Agaricales↗
PubMed1989

Magnetic resonance spectral characterization of the heme active site of Coprinus cinereus peroxidase.

Examination of the peroxidase isolated from the inkcap Basidiomycete Coprinus cinereus shows that the 42,000-dalton enzyme contains a protoheme IX prosthetic group. Reactivity assays and the electronic absorption spectra of native Coprinus peroxidase and several of its ligand complexes indicate that this enzyme has characteristics similar to those reported for horseradish peroxidase. In this paper, we characterize the H2O2-oxidized forms of Coprinus peroxidase compounds I, II, and III by electronic absorption and magnetic resonance spectroscopies. Electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) studies of this Coprinus peroxidase indicate the presence of high-spin Fe(III) in the native protein and a number of differences between the heme site of Coprinus peroxidase and horseradish peroxidase. Carbon-13 (of the ferrous CO adduct) and nitrogen-15 (of the cyanide complex) NMR studies together with proton NMR studies of the native and cyanide-complexed Coprinus peroxidase are consistent with coordination of a proximal histidine ligand. The EPR spectrum of the ferrous NO complex is also reported. Protein reconstitution with deuterated hemin has facilitated the assignment of the heme methyl resonances in the proton NMR spectrum.

Basidiomycota↗
PubMed1990

Involvement of Coprinus endonuclease in preparing substrate for in vitro recombination.

A functional recombination assay involving the tetracycline mutant plasmids, pUW1 and pUW4, was used to assess (i) the nature of the DNA substrates needed and (ii) the involvement of Coprinus endonuclease in preparing substrate, for the RecA-directed recombination process. A gapped circular plasmid and a linear or a nicked circular plasmid are efficient substrate combinations in this system to achieve a 160-fold increase in the in vitro recombination frequency over the control levels. The Coprinus endonuclease obtained from early meiotic prophase can produce such substrates. The recombination frequency obtained with the combination of gapped pUW1 plasmids initially relaxed by the Coprinus endonuclease and linear pUW4 plasmids produced by the site-specific BamHI digest is 10-fold lower than that obtained when both substrates are digested by BamHI. The results suggest that the Coprinus endonuclease creates random nicks on plasmid DNA. Glyoxal gel electrophoretic analysis was used to confirm this random nicking activity of Coprinus endonuclease.

Agaricales↗
PubMed1988

Purification and characterization of an endonuclease from fruiting caps of basidiomycete Coprinus cinereus.

An endonuclease was purified from the cap tissues of basidiocarp of Coprinus cinereus collected at early meiotic prophase. It has an optimal activity at pH 7.0 and 37 degrees C. It is a cationic enzyme with a molecular mass of 22 kDa by gel filtration, and contains a 12-kDa and a 14-kDa peptide as revealed by SDS gel electrophoresis and Western blot analysis. An antiserum was produced in rabbits against the purified Coprinus endonuclease. The specificity of this antiserum was demonstrated in a dot-blot analysis and, more critically, in an immunoinhibition of endonuclease activity. The Coprinus endonuclease requires Mg2+ and/or Ca2+ as co-factors. Ca2+ is more efficient than Mg2+ while the effect of combining both co-factors is the highest. The Coprinus endonuclease has a substrate preference for single-strand and supercoiled DNA. It gives only single-strand nicks on supercoiled DNA at low enzyme concentration and limited time of incubation. At high enzyme concentration and/or long incubation time, double-strand fragmentation occurred. As is discussed, this endonuclease is believed to be involved in the early phase of meiotic recombination.

Agaricales↗
PubMed1988

Purification, crystallization, and characterization of peroxidase from Coprinus cinereus.

Peroxidase (donor: H2O2 oxidoreductase [EC 1.11.1.7]) was purified from a culture broth of an inkcap Basidiomycete, Coprinus cinereus S.F. Gray. A single component containing a low amount of carbohydrate was isolated by affinity chromatography on concanavalin A-Sepharose and crystallized from ammonium sulfate solution. The enzyme is an acidic protein (pI 3.5) and consists of a single polypeptide chain having the molecular weight of 41,600 daltons. The enzyme contains one protohemin per molecule and exhibits the characteristic absorption, circular dichroism, and magnetic circular dichroism spectra of a heme-protein. The Coprinus peroxidase forms two characteristic intermediate compounds, I and II, and the rate constants for hydrogen peroxide and guaiacol had similar values to those for higher plant peroxidases. The ferric enzyme formed a cyanide compound with a dissociation constant similar to those for higher plant enzyme, but the dissociation constant of the ferrous enzyme-cyanide was large. The chemical composition of Coprinus peroxidase showed 381 amino acid residues, 1 glucosamine, 3 true sugars, 3 calcium, and 1 non-heme iron other than 1 protohemin. The secondary structure of the fungal enzyme was very similar to that of horseradish peroxidase.

Agaricales↗
PubMed1991

An endo-exonuclease from meiotic tissues of the basidiomycete Coprinus cinereus. Its purification and characterization.

An endo-exonuclease has been identified and partially purified from the basidiocarp tissues of the basidiomycete Coprinus cinereus, which include synchronous meiosis at karyogamy-pachytene stages. Its peak activity appears during the meiotic prophase. The Coprinus endo-exonuclease has a single-strand specific endonuclease activity that converts the supercoiled DNA to relaxed DNA. The endonucleolytic cleavage of single-strand DNA generates 3'-phosphomonoester termini. It is also a single-strand-specific exonuclease and it hydrolyzes linear DNA in a 3' to 5' direction, but is unable to hydrolyze single-strand DNA having a 3'-phosphomonoester terminus. It requires Mg2+ with an optimal concentration of 25 mM. It has an optimal pH of 8.3, a peak enzyme activity at 50 degrees C, and it contains a single 43-kilodalton polypeptide. Coprinus meiotic endo-exonuclease may be involved in the substrate preparation for meiotic recombination.

Basidiomycota↗
PubMed1990

[Serine proteinase from the higher basidiomycetes of Coprinus genus].

A thiol-dependent serine proteinase has been isolated for the first time from a higher basidiomycete Coprinus 7N culture filtrate by affinity chromatography on bacitracin-Sepharose combined with ion-exchange chromatography on DEAE-Sepharose. This procedure resulted in a homogeneous enzyme with 32-fold purification and 55% yield. The enzyme has a molecular mass of 33,000 Da and pI of 8.5; its amino acid composition appears as follows: Lys7, His7, Arg10, Asx29, Thr24, Ser30, Glx19, Pro13, Gly39, Ala40, Cys2-3, Val23, Met1-2, Ile14, Leu13, Tyr6, Phe7. The enzyme shows the optimal activity towards Z-Ala-Ala-Leu-pNA at 8.5 and is stable at pH 6-9. The temperature optimum of the enzyme activity lies at 37 degrees C. The proteinase is completely inactivated by the specific inhibitors of serine proteinases, diisopropylfluorophosphate and phenylmethylsulfonylfluoride, as well as by the SH-group reagent, p-chloromercuribenzoate. The Coprinus 7N proteinase hydrolyzes, azocasein, azoalbumin, hemoglobin, fibrin and synthetic chromogenic peptide substrates, e. g., Z-Ala-Ala-Leu-pNA, Z-Gly-gly-Leu-pNA. Some properties of the Coprinus 7N proteinase are very similar to those of thiol-dependent serine proteinases from bacilli, actinomycetes, fungi and plants which form a subfamily of thiol-dependent serine proteinases within the family of subtilisins.

Amino Acid Sequence↗
PubMed1987

DNA-mediated transformation of the basidiomycete Coprinus cinereus.

We have developed a simple and efficient transformation system for the agaric fungus, Coprinus cinereus. Protoplasts were prepared from asexual spores that harbor one or two mutations in the structural gene for tryptophan synthetase. The protoplasts can be stably transformed using the cloned Coprinus gene at a frequency of 1 in 10(4) viable protoplasts. A variety of molecular events accompanies the formation of stable transformants, including insertion of the transforming DNA at the homologous locus. The transforming DNA is stable through cell division, mating, fruiting body formation, and meiosis.

Agaricales↗
PubMed1977

Genetics and function of isocitrate lyase in Coprinus.

Thirteen chromosomal loci have been identified which affect acetate metabolism in Coprinus. Mutants at only two loci, acu-l and acu-7, are deficient in isocitrate lyase (ICL) (EC 4.1.3.1) activity. acu-1 mutants are unable to induce ICL because they lack acetyl-CoA synthetase which is required to convert acetate to the metabolic inducer of ICL. acu-7 is the structural gene for ICL. This was shown by selecting temperature sensitive acu+ revertants resulting from a second mutation within the acu-7 gene. One such revertant was shown to produce an ICL protein which was more thermolabile than the wild type enzyme. Other workers have postulated that ICL activity is important during asexual morphogenesis in fungi. No evidence was found for this in Coprinus. The morphological mutant oidial, which produces abundant asexual spores even in submerged culture, had the same low uninduced level of ICL activity as the wild type. Moreover, an acu-7 mutation had no effect on the expression of the oidial phenotype.

Acetates↗
PubMed1992

Proton nuclear Overhauser effect study of the heme active site structure of Coprinus macrorhizus peroxidase.

Proton nuclear Overhauser effect and paramagnetic relaxation measurements have been used to define more extensively the heme active site structure of Coprinus macrorhizus peroxidase, CMP (previously known as Coprinus cinereus peroxidase), as the ferric low-spin cyanide ligated complex. The results are compared with other well-characterized peroxidase enzymes. The NMR spectrum of CMPCN shows changes in the paramagnetically shifted resonances as a function of time, suggesting a significant heme disorder for CMP. The presence of proximal and distal histidine amino acid residues are common to the heme environments of both CMPCN and HRPCN. However, the upfield distal arginine signals of HRPCN are not evident in the 1H-NMR spectra of CMPCN.

Binding Sites↗
PubMed1988

Basidiospore allergens: analysis of Coprinus quadrifidus spore, cap, and stalk extracts.

Atopic individuals with symptoms of respiratory allergy have been shown to have IgE-mediated reactions to spores from the basidiomycete fungi. Because our earlier studies suggested that parts of the fungus other than spores may contain allergens, the current study was performed. Extracts of Coprinus quadrifidus spores, caps, and stalks were prepared and fractionated by gel filtration column chromatography on Sephadex G-75. Analysis of column fractions of each separation by ultraviolet absorption demonstrated at least three peaks of absorbency in spore, cap, and stalk extracts. Pooled column fractions were analysed by direct radio-allergosorbent test (RAST) using pooled sera from C. quadrifidus skin-test positive subjects. Enhanced allergenic activity was present in the same portion of the column eluate for cap, spore, and stalk fractionations, corresponding to a molecular weight of approximately 10.5-25 kD. Pools with allergenic activity were used to test volunteers by skin prick and RAST. Skin test and RAST activities were similar for each of the three Coprinus extracts, with stalk being the most potent. Evidence of common allergenic epitopes was demonstrated by inhibition of spore RAST by spore, cap, and stalk extracts. These results suggest that C. quadrifidus cap and stalk extracts contain allergens similar to those in spores extract and may provide useful sources of allergen for further study.

Agaricales↗
PubMed1992

Poisoning by Coprinus atramentarius.

The ink cap--Coprinus atramentarius (Bulliard ex Fries) Fries--is responsible for poisoning when ingested with alcohol. The investigation of the "Coprinus syndrome," although a minor poisoning incident, stimulated numerous research programs because the results were expected to yield a novel drug useful during the treatment of alcoholism. This work led to the identification of the active principle--coprine--and to an explanation of its mode of action; nevertheless, detailed toxicology investigations have shown that the mutagenic and gonadotoxic properties of this compound made it unsuitable for therapeutic use. Our current knowledge of the poisoning, the chemistry of the toxin, and its mode of action are here reviewed.

Aldehyde Oxidoreductases↗
PubMed1991

Targeted transformation in Coprinus cinereus.

We examined the influence of DNA form and size on the arrangement and genomic location of transforming DNA sequences in the basidiomycete Coprinus cinereus. Protoplasts with either single or double mutations in the tryptophan synthetase (TRP1) gene were transformed with cloned copies of this gene which contained only a single DNA strand, contained a specific single nick within the C. cinereus sequences (4.8 kb), contained a specific double-strand break, or contained an additional 35 kb of flanking genomic sequences. Gene replacement events were recovered when each DNA type was used. However, none of these substrates offers a substantial improvement in transformation or targeting frequency when compared to supercoiled circular DNA, which has allowed recovery of both gene replacements as well as homologous insertions in 5% of the transformants analyzed. The frequency of transformants carrying tandem insertions with multiple copies of the transforming DNA was reduced when single-stranded DNA was used, and increased when DNA containing double-strand breaks was used. These results have important implications for the efficient design of targeted transformation and co-transformation experiments.

Blotting, Southern↗