Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A laccase with a novel N-terminal sequence, a low molecular mass of 43 kDa smaller than those of previously reported laccases, a pH optimum of 4, and a temperature optimum at 70 degrees C was isolated from fresh fruiting bodies of the mushroom Tricholoma giganteum. The activity of the enzyme rose steadily from 20 to 50 degrees C, increased very slowly from 50 to 70 degrees C, and fell slightly when the temperature was further increased to 80 degrees C. The activity of the laccase underwent little changes over the pH range 3.0-5.0. However, the enzyme activity dwindled to nothing after exposure to 100 degrees C for 10 min and when the ambient pH was 7 or above. The procedure used for purifying the enzyme included ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose, and FPLC-gel filtration on Superdex 75. The laccase was unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel and CM-cellulose. It inhibited HIV-1 reverse transcriptase with an IC(50) of 2.2 microM.
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PMID:Purification of a novel low-molecular-mass laccase with HIV-1 reverse transcriptase inhibitory activity from the mushroom Tricholoma giganteum. 1476 29

A laccase with a novel N-terminal sequence was purified from fresh fruiting bodies of the edible wild mushroom Albatrella dispansus using a procedure that entailed ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel and Con A-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. In contrast to most of the previously reported laccases from mushroom mycelia, the laccase was unadsorbed on DEAE-cellulose. Although it was also unadsorbed on Affi-gel blue gel, it was adsorbed on Con A-Sepharose, indicating that it is a glycoprotein. It exhibited a molecular mass of 62kDa in gel filtration and SDS-PAGE. The activity of the laccase increased with temperature from 20 to 70 degrees C, and notably remained high at 80 degrees C. The pH optimum for the enzyme was around 4. Enzyme activity was indiscernible at pH 8 and pH 9. The laccase did not exert any inhibitory activity toward HIV-1 reverse transcriptase at a concentration of 1mg/ml, unlike some previously reported mushroom proteins.
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PMID:A novel laccase with fair thermostability from the edible wild mushroom (Albatrella dispansus). 1517 17

A laccase with a novel N-terminal sequence, a molecular mass of 63kDa, and inhibitory activity toward HIV-1 reverse transcriptase (IC(50)=9.5microM) was isolated from dried fruiting bodies of the monkey head mushroom Hericium erinaceum. A chromatographic procedure involving ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-Sepharose and fast protein liquid chromatography-gel filtration on Superdex 75 was employed. The laccase was adsorbed on DEAE-cellulose and Q-Sepharose but unadsorbed on CM-cellulose. High activity of the enzyme was observed at pH 3-5 and at 50-80 degrees C. Its activity was completely abolished at pH 8 and 9 and after boiling for 10min. A temperature of 50 degrees C and a pH of 5.0 were optimal for its activity.
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PMID:A new laccase from dried fruiting bodies of the monkey head mushroom Hericium erinaceum. 1531 67

A purification scheme involving ion exchange chromatography on diethylaminoethyl (DEAE) cellulose, carboxymethyl (CM) cellulose, and Q-Sepharose, followed by fast protein liquid chromatography-gel filtration on Superdex 75, was utilized to isolate a laccase from the fruiting bodies of the mushroom Pleurotus eryngii. The laccase was adsorbed on DEAE-cellulose and Q-Sepharose and unadsorbed on CM-cellulose. The molecular mass of the laccase in sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 34 kDa. The laccase activity was maximal at 70 degrees C and remained high at 80 degrees C. High activity of the laccase was maintained at ph 3 to 5. The activity underwent an abrupt decline at pH 6 and 7 and was indiscernible at ph 8 and 9. The laccase exhibited an inhibitory activity toward HIV-1 reverse transcriptase with an IC50 of 2.2 microM. Its N-terminal sequence was dissimilar to those of laccase isoenzymes previously isolated from cultured mycelia of the same species.
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PMID:Purification of a laccase from fruiting bodies of the mushroom Pleurotus eryngii. 1607 91

Three novel laccase isozyme genes, lacA, lacB, and lacC, have been identified from basidiomycete Trametes sp. AH28-2. These genes display a high similarity with other basidiomycete laccases at the amino acid level. An inferred TATA box and several putative CAAT, MRE, XRE, and CreA consensus sequences were identified in the lacA, lacB, and lacC promoter regions. Different from the TATA boxes of lacA and lacB at about -100, the TATA box of lacC is located at -172. For all the isozymes, copper ion is essential for laccase synthesis in Trametes sp. AH28-2. More interestingly, different aromatic compounds can selectively induce the production of distinct laccase isozymes, with o-toluidine inducing the expression of laccase A (LacA) while 3,5-dihydroxytoluene mainly stimulating the production of laccase B (LacB). Quantitative reverse transcriptase-polymerase chain reaction showed that the accumulation of laccase messenger RNA transcripts is accompanied by the increase of corresponding enzyme activity in cultures. The glucose-repression effect on laccase expression in Trametes sp. AH28-2 was also observed. Furthermore, lower Cu2+ concentration (lower than 0.5 mM) can induce LacA and a novel laccase (LacC), and the latter will disappear when Cu2+ concentration is increased up to 1-2 mM. Upon induction by 3,5-dihydroxytoluene, the ratio of LacA to LacB decreased in the later phase of induction.
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PMID:Cloning of novel laccase isozyme genes from Trametes sp. AH28-2 and analyses of their differential expression. 1628 98

A cDNA encoding for laccase (Lcc1) was isolated from the ligninolytic fungus Trametes versicolor by reverse transcriptase polymerase chain reaction. The Lcc1 gene was subcloned into the Pichia methanolica expression vector pMETalphaA and transformed into the P. methanolica strains PMAD11 and PMAD16. The extracellular laccase activity of the PMAD11 recombinants was found to be 1.3-fold higher than that of the PMAD16 recombinants. The identity of the recombinant protein was further confirmed by immunodetection using the Western blot analysis. As expected, the molecular mass of the mature laccase was 64.0 kDa, similar to that of the native form. The effects of copper concentration, cultivation temperature, pH and methanol concentration in the BMMY on laccase expression were investigated. The laccase activity in the PMAD11 recombinant was up to 12.6 U ml(-1) by optimization.
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PMID:Optimization of the expression of a laccase gene from Trametes versicolor in Pichia methanolica. 1629 28

A protein demonstrating laccase activity and potent inhibitory activity towards human immunodeficiency virus (HIV)-1 reverse transcriptase (IC50 1.2 microM) was isolated from fresh fruiting bodies of the medicinal mushroom Ganoderma lucidum. The laccase had a novel N-terminal sequence and a molecular mass of 75 kDa, which is higher than the range (55-56 kDa) reported for most other mushroom laccases. It was isolated by sequential chromatography on DEAE-cellulose and Affi-gel blue gel and adsorption on Con A-Sepharose. Unlike some of the previously isolated laccases, it was adsorbed only on Con A-Sepharose. The enzyme required a pH of 3-5 and a temperature of 70 degrees C to exhibit maximal activity. Minimal activity was detected at pH 6 and 7. Activity was undetectable at pH 8 and 9 and after exposure to 100 degrees C for 10 min.
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PMID:A laccase from the medicinal mushroom Ganoderma lucidum. 1663 32

Hot water extracts of 16 species of mushrooms, including both edible and medicinal mushrooms, were screened for human immunodeficiency virus (HIV)-1 reverse transcriptase (RT) inhibitory activity. Extracts of Lactarius camphoratus, Trametes suaveolens, Sparassis crispa, Pleurotus sajor-caju, Pleurotus pulmonarius, and Russula paludosa elicited over 50% inhibition when tested at the concentration of 1 mg/ml. The extract of R. paludosa demonstrated the highest inhibitory activity on HIV-1 RT (97.6%). Fraction SU2, purified from R. paludosa extract by anion exchange chromatography on DEAE-cellulose and gel filtration on Superdex 75, exhibited potent inhibitory activity on HIV-1 RT. At the concentrations of 1 mg/ml, 0.2 mg/ml, and 0.04 mg/ml, the inhibition ratios were 99.2%, 89.3%, and 41.8%, respectively, giving an IC50 of 11 microM. The molecular mass of SU2 was 4.5 kDa and its N-terminal amino acid sequence was determined to be KREHGQHCEF. The peptide was devoid of hemagglutinating, ribonuclease, antifungal, protease, protease inhibitory, and laccase activities.
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PMID:A peptide with HIV-1 reverse transcriptase inhibitory activity from the medicinal mushroom Russula paludosa. 1711 95

Ligninolytic enzymes produced by white-rot fungi are effective degraders of recalcitrant aromatic environmental pollutants. However, gene sequences of these enzymes are rich in CpG dinucleotides, which are particularly unfavorable to efficient expression in plants. In order to develop a phytoremediation technique with a ligninolytic enzyme-producing transgenic plant, laccase cDNA (scL) from white-rot fungus Schizophyllum commune was used as a model ligninolytic enzyme, and we attempted to obtain the efficient expression of scL in a transgenic tobacco plant by decreasing the CpG-dinucleotide motif content. We constructed a mutagenized scL sequence, scL12, decreasing the CpG-dinucleotide motif content by 12%, and scL12 was introduced into the tobacco plant. Much higher laccase activity was detected in transgenic scL12 plants than in transgenic scL plants and wild-type plants. Using reverse transcriptase-PCR analysis, scL12 was translated in transgenic scL12 plants whereas mRNA of scL was not detected in the transgenic scL plants, and scL, which is the product of the scL12 gene, was produced in the transgenic scL12 plants using native-polyacrylamide gel electrophoresis analysis. Moreover, transgenic scL12 plants were able to remove trichlorophenol more effectively than transgenic scL plants and wild-type plants. These results suggest that decreasing CpG-dinucleotide motif content in fungal target genes is a useful method for efficient expression of these genes in transgenic plants.
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PMID:Efficient expression of laccase gene from white-rot fungus Schizophyllum commune in a transgenic tobacco plant. 1862 19

In forest soils, ectomycorrhizal and saprotrophic Agaricales differ in their strategies for carbon acquisition, but share common gene families encoding multi-copper oxidases (MCOs). These enzymes are involved in the oxidation of a variety of soil organic compounds. The MCO gene family of the ectomycorrhizal fungus Laccaria bicolor is composed of 11 genes divided into two distinct subfamilies corresponding to laccases (lcc) sensu stricto (lcc1 to lcc9), sharing a high sequence homology with the coprophilic Coprinopsis cinerea laccase genes, and to ferroxidases (lcc10 and lcc11) that are not present in C. cinerea. The fet3-like ferroxidase genes lcc10 and lcc11 in L. bicolor are each arranged in a mirrored tandem orientation with an ftr gene coding for an iron permease. Unlike C. cinerea, L. bicolor has no sid1/sidA gene for siderophore biosynthesis. Transcript profiling using whole-genome expression arrays and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) revealed that some transcripts were very abundant in ectomycorrhizas (lcc3 and lcc8), in fruiting bodies (lcc7) or in the free-living mycelium grown on agar medium (lcc9 and lcc10), suggesting a specific function of these MCOs. The amino acid composition of the MCO substrate binding sites suggests that L. bicolor MCOs interact with substrates different from those of saprotrophic fungi.
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PMID:Phylogenetic analysis, genomic organization, and expression analysis of multi-copper oxidases in the ectomycorrhizal basidiomycete Laccaria bicolor. 1924 15


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