title: The identification and characterization of four laccases from the plant pathogenic fungus Rhizoctonia solani.
abstract: Four distinct laccase genes, lcc1, lcc2, lcc3 and lcc4, have been identified in the fungus Rhizoctonia solani. Both cDNA and genomic copies of these genes were isolated and characterized. Hybridization analyses indicate that each of the four laccase genes is present in a single copy in the genome. The R. solani laccases can be divided into two groups based on their protein size, intron/exon organization, and transcriptional regulation. Three of these enzymes have been expressed in the fungus Aspergillus oryzae. Two of the recombinant laccases, r-lcc1 and r-lcc4, as well as the native lcc4 enzyme were purified and characterized. The purified proteins are homodimeric, comprised of two subunits of approximately 66kDa for lcc4 and 50-100kDa for the recombinant lcc1 protein. These laccases have spectral properties that are consistent with other blue copper proteins. With syringaldazine as a substrate, lcc4 has optimal activity at pH7, whereas lcc1 has optimal activity at pH6.
authors.affiliation: Novo Nordisk Biotech, Davis, CA 95616, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Wahleithner
authors.forename: F
authors.initials: F
authors.lastname: Xu
authors.forename: K M
authors.initials: KM
authors.lastname: Brown
authors.forename: S H
authors.initials: SH
authors.lastname: Brown
authors.forename: E J
authors.initials: EJ
authors.lastname: Golightly
authors.forename: T
authors.initials: T
authors.lastname: Halkier
authors.forename: S
authors.initials: S
authors.lastname: Kauppinen
authors.forename: A
authors.initials: A
authors.lastname: Pederson
authors.forename: P
authors.initials: P
authors.lastname: Schneider
mesh_terms: D000595:Amino Acid Sequence; D015139:Blotting, Southern; D004591:Electrophoresis, Polyacrylamide Gel; D005784:Gene Amplification; D017343:Genes, Plant; D007527:Isoenzymes / Q000235:genetics* / Q000302:isolation & purification; D042845:Laccase; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D012232:Rhizoctonia / Q000201:enzymology* / Q000235:genetics*; D012967:Sodium Dodecyl Sulfate; D014158:Transcription, Genetic
chemical_list: D007527:Isoenzymes; D011994:Recombinant Proteins; D012967:Sodium Dodecyl Sulfate; D010088:Oxidoreductases; D042845:Laccase