Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.10.3.2 (laccase)
 4,656 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The rhg1 gene or genes lie at a recessive or co-dominant locus, necessary for resistance to all Hg types of the soybean (Glycine max (L.) Merr.) cyst nematode (Heterodera glycines I.). The aim here was to identify nucleotide changes within a candidate gene found at the rhg1 locus that were capable of altering resistance to Hg types 0 (race 3). A 1.5 +/- 0.25 cM region of chromosome 18 (linkage group G) was shown to encompass rhg1 using recombination events from four near isogenic line populations and nine DNA markers. The DNA markers anchored two bacterial artificial chromosome (BAC) clones 21d9 and 73p6. A single receptor like kinase (RLK; leucine rich repeat-transmembrane-protein kinase) candidate resistance gene was amplified from both BACs using redundant primers. The DNA sequence showed nine alleles of the RLK at Rhg1 in the soybean germplasm. Markers designed to detect alleles showed perfect association between allele 1 and resistance to soybean cyst nematode Hg types 0 in three segregating populations, fifteen additional selected recombination events and twenty-two Plant Introductions. A quantitative trait nucleotide (QTN) [corrected] in the RLK at rhg1 was inferred that alters A87 to V87 in the context of H274 rather than N274. [corrected] Contiguous DNA sequence of 315 kbp of chromosome 18 (about 2 cM) contained additional gene candidates that may modulate resistance to other Hg-types including a variant laccase, a hydrogen-sodium ion antiport and two proteins of unknown function. A molecular basis for recessive and co-dominant resistance that involves interactions among paralagous disease-resistance genes was inferred that would improve methods for developing new nematode-resistant soybean cultivars.
Mol Genet Genomics 2006 Dec
PMID:Genomic analysis of the rhg1 locus: candidate genes that underlie soybean resistance to the cyst nematode. 1702 28

Hsp70 proteins are a well-known class of chaperones that have also been described to have roles in cellular regulation. Here, we show that a Cryptococcus neoformans Hsp70 homologue Ssa1 acts as a DNA-binding transcriptional co-activator of the fungal virulence factor, laccase, via binding to a GC-rich element within the 5'-UAS in response to glucose starvation, iron, copper, calcium and temperature. In addition, Ssa1 forms a regulatory complex with heat shock transcription factor and TATA-binding protein during laccase induction. Furthermore, deletion of Ssa1 results in reduced laccase and attenuated virulence using a mouse model. These results indicate that Hsp70 functions as a stress-related transcriptional co-activator required for fungal virulence.
Mol Microbiol 2006 Nov
PMID:The Hsp70 member, Ssa1, acts as a DNA-binding transcriptional co-activator of laccase in Cryptococcus neoformans. 1704 Apr 92

Selective hydroxylation of aromatic compounds is among the most challenging chemical reactions in synthetic chemistry and has gained steadily increasing attention during recent years, particularly because of the use of hydroxylated aromatics as precursors for pharmaceuticals. Biocatalytic oxygen transfer by isolated enzymes or whole microbial cells is an elegant and efficient way to achieve selective hydroxylation. This review gives an overview of the different enzymes and mechanisms used to introduce oxygen atoms into aromatic molecules using either dioxygen (O(2)) or hydrogen peroxide (H(2)O(2)) as oxygen donors or indirect pathways via free radical intermediates. In this context, the article deals with Rieske-type and alpha-keto acid-dependent dioxygenases, as well as different non-heme monooxygenases (di-iron, pterin, and flavin enzymes), tyrosinase, laccase, and hydroxyl radical generating systems. The main emphasis is on the heme-containing enzymes, cytochrome P450 monooxygenases and peroxidases, including novel extracellular heme-thiolate haloperoxidases (peroxygenases), which are functional hybrids of both types of heme-biocatalysts.
Cell Mol Life Sci 2007 Feb
PMID:Enzymatic hydroxylation of aromatic compounds. 1722 Nov 66

Benzo[a]pyrene (BaP) is listed as a priority pollutant by the U.S. Environmental Protection Agency because it is one of the most potent carcinogens of all known polycyclic aromatic hydrocarbons (PAHs). The biodegradation of BaP is of interest as a means for mitigating its effects in polluted ecosystems. In the present study, BaP was oxidized with laccase from Trametes versicolor, which was immobilized on functionalized kaolinite particles, and the cytotoxicity and genotoxicity of BaP and its degradation intermediates were measured in human HaCaT keratinocytes and A3 T lymphocytes. Cytotoxicity was assessed by fluorescein diacetate (FDA) uptake, while the alkaline Comet assay measured genotoxicity, using tail moment, tail DNA content, and tail length as metrics for DNA damage. On the basis of first-order reaction kinetics, the half life (t(1/) (2)) for the oxidization of BaP by immobilized laccase was 58.5 hr. After 87 hr of oxidation, 20 muM of BaP had decreased to 9.6 muM. HPLC analysis identified 1,6-benzo[a]pyrene quinone (1,6-BaQ), 3,6-benzo[a]pyrene quinone (3,6-BaQ), and 6,12-benzo[a]pyrene quinone (6,12-BaQ) among the oxidation products. Most treatments of HaCaT cells and A3 lymphocytes with BaP or its quinone intermediates resulted in significant decreases in viability (P < 0.05); dose-dependent decreases in cell viability were detected at concentrations of 0.1, 1, and 5 muM, but none of these treatments resulted in decreases of >30%. While treatment of HaCaT cells with as little as 0.1 muM 6,12-BaQ caused significant DNA damage, DNA damage was detected in HaCaT cells only with 1 and 5 muM 1,6-BaQ and 3,6-BaQ, and 5 muM BaP. In Comet assays conducted with A3 lymphocytes, all three quinone intermediates caused significant increase in tail DNA content at 1 and 5 muM. The results indicate that immobilized laccase is capable of degrading BaP, but several of those biodegradation products produce significant levels of DNA damage in human cells.
Environ Mol Mutagen 2007 Mar
PMID:Biodegradation of benzo[a]pyrene with immobilized laccase: genotoxicity of the products in HaCat and A3 cells. 1725 27

Laccase (E.C. 1.10.3.2) is one of the well-studied enzymes used for bioremediation of xenobiotics such as phenols, anilines, etc. Its broad substrate specificity offers a wide opportunity for screening pollutants in order to predict potential targets for degradation. Present study utilizes protein-ligand docking as a tool to achieve the said. For virtual screening, a set of pollutants were selected from five different industries from EPA. X-ray crystal structures of laccase enzymes were taken from the Brookhaven Protein Data Bank (PDB). Two-dimensional structures of pollutants were downloaded from the NCBI Pubchem, which were further converted into three-dimensional structures using CORINA. Protein-ligand docking was carried out using GOLD. Nearly 30 and 17% of the selected datasets showed the best average GOLD fitness score for fungal and bacterial laccase enzyme respectively, suggesting thereby that laccase might be able to oxidize these pollutants. Moreover, in few cases like anthracene, phenanthrene, etc., there is experimental data to support this hypothesis. Similar kind of work would be helpful to find putative pollutants for other biodegradative enzymes.
J Mol Graph Model 2008 Jan
PMID:An in silico [correction of insilico] approach to bioremediation: laccase as a case study. 1760 96

A miniTn5-induced mutant of a melanin-producing strain of Sinorhizobium meliloti (CE52G) that does not produce melanin was mapped to a gene identified as a probable thioredoxin gene. It was proved that the thiol-reducing activity of the mutant was affected. Addition to the growth medium of substrates that induce the production of melanin (L-tyrosine, guaiacol, orcinol) increased the thioredoxin-like (trxL) mRNA level in the wild-type strain. The mutant strain was affected in the response to paraquat-induced oxidative stress, symbiotic nitrogen fixation, and both laccase and tyrosinase activities. The importance of thioredoxin in melanin production in bacteria, through the regulation of laccase or tyrosinase activities, or both, by the redox state of structural or catalytic SH groups, is discussed.
Mol Plant Microbe Interact 2007 Aug
PMID:A thioredoxin of Sinorhizobium meliloti CE52G is required for melanin production and symbiotic nitrogen fixation. 1772 47

CueO is a multicopper oxidase (MCO) that is involved in the homeostasis of Cu in Escherichia coli and is the sole cuprous oxidase to have ever been found. Differing from other MCOs, the substrate-binding site of CueO is deeply buried under a methionine-rich helical region including alpha-helices 5, 6, and 7 that interfere with the access of organic substrates. We deleted the region Pro357-His406 and replaced it with a Gly-Gly linker. The crystal structures of a truncated mutant in the presence and in the absence of excess Cu(II) indicated that the scaffold of the CueO molecule and metal-binding sites were reserved in comparison with those of CueO. In addition, the high thermostability of the protein molecule and its spectroscopic and magnetic properties due to four Cu centers were also conserved after truncation. As for functions, the cuprous oxidase activity of the mutant was reduced to ca 10% that of recombinant CueO owing to the decrease in the affinity of the labile Cu site for Cu(I) ions, although activities for laccase substrates such as 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), p-phenylenediamine, and 2,6-dimethoxyphenol increased due to changes in the access of these organic substrates to the type I Cu site. The present engineering of CueO indicates that the methionine-rich alpha-helices function as a barrier to the access of bulky organic substrates, which provides CueO with specificity as a cuprous oxidase.
J Mol Biol 2007 Oct 12
PMID:Structure and function of the engineered multicopper oxidase CueO from Escherichia coli--deletion of the methionine-rich helical region covering the substrate-binding site. 1780 14

A laccase gene from Trametes sp. 420 was recombinantly expressed in Pichia pastoris, producing the enzyme rLacD. Six mutant enzymes were produced by site-directed mutation at six potential glycosylation sites in the enzyme rLacD respectively. To probe the mutants with lower activities sensitively and specifically, the antiserum containing specific polyclonal antibodies were prepared by immunizing healthy male rabbits, about 4-month-old and 2 kilogram weight, using pure rLacD as an immunogen. Antibodies were collected after the fifth immunization injection. The antiserum had titres of 1:32 in double immunodiffusion test and of 1:128,000 in enzyme-linked immunosorbent assay (ELISA). The results obtained by Western blot analysis showed that the antiserum could react with rLacD and its mutants with highly specific and sensitive affinities.
Cell Mol Immunol 2007 Aug
PMID:Preparation and application of polyclonal antibody against a recombinant laccase. 1794 Nov 75

Laccases are multicopper-containing oxidases that catalyze the oxidation of many aromatic compounds with concomitant reduction of oxygen to water. Interest in this enzyme has arisen in many fields of industry, including detoxification, wine stabilization, paper processing, and enzymatic conversion of chemical intermediates. In this study, we cloned a laccase gene (GLlac1) from the white-rot fungus Ganoderma lucidum. The cloned gene consists of 4,357 bp, with its coding region interrupted by nine introns, and the upstream region has putative CAAT and TATA boxes as well as several metal responsive elements (MREs). We also cloned a full-length cDNA of GLlac1, which contains an uninterrupted open reading frame (ORF) of 1,560 bp coding for 520 amino acids with a putative 21-residue signal sequence. The DNA and deduced amino acid sequences of GLlac1 were similar but not identical to those of other fungal laccases. GLlac1 was released from the cells when expressed in P. pastoris, and had high laccase activity. In addition, GLlac1 conferred antioxidative protection from protein degradation, and thus may be useful in bio-medical applications.
Mol Cells 2008 Feb 29
PMID:Molecular cloning and expression of a laccase from Ganoderma lucidum, and its antioxidative properties. 1831 22

Recently, it has been demonstrated that the opportunistic fungal pathogen Cryptococcus neoformans can synthesize authentic immunomodulatory prostaglandins. The mechanism by which this takes place is unclear as there is no cyclooxygenase homologue in the cryptococcal genome. In this study, we show that cryptococcal production of both PGE(2) and PGF(2 alpha) can be chemically inhibited by caffeic acid, resveratrol and nordihydroguaiaretic acid. These polyphenolic molecules are frequently used as inhibitors of lipoxygenase enzymes; however, blast searches of the cryptococcal genome were unable to identify any homologues of mammalian, plant or fungal lipoxygenases. Next we investigated cryptococcal laccase, an enzyme known to bind polyphenols, and found that either antibody depletion or genetic deletion of the primary cryptococcal laccase (lac1 Delta) resulted in a loss of cryptococcal prostaglandin production. To determine how laccase is involved, we tested recombinant laccase activity on the prostaglandin precursors, arachidonic acid (AA), PGG(2) and PGH(2). Using mass spectroscopy we determined that recombinant Lac1 does not modify AA or PGH(2), but does have a marked activity toward PGG(2) converting it to PGE(2) and 15-keto-PGE(2). These data demonstrate a critical role for laccase in cryptococcal prostaglandin production, and provides insight into a new and unique fungal prostaglandin pathway.
Mol Microbiol 2008 Jun
PMID:The role of laccase in prostaglandin production by Cryptococcus neoformans. 1841 Apr 94


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