Primary structure of a Japanese lacquer tree laccase as a prototype enzyme of multicopper oxidases.
The cDNA library of the Japanese lacquer tree (Rhus vernicifera) was constructed by the reverse transcription of mRNA. A cDNA encoding laccase was amplified by PCR using primers based on the N-terminal amino acid sequences of the purified laccase and its peptide fragments formed by digestions with chymotrypsin and trypsin, and subcloned. The laccase cDNA clone contained a single, large open reading frame of 1599 nucleotides, encoding a protein of 533 amino acids with a calculated molecular mass of 58981 Da. The lacquer laccase was found to have 42 to 62% identity with other plant laccases and 20 to 24% identity with microorganism laccases at the deduced amino acid level. Differing from microorganism laccases the lacquer laccase utilizes a Met residue in addition to one Cys and two His residues to construct the type 1 Cu site. The secondary structure of the lacquer laccase was predicted to mainly consist of the beta-structure (28.7%) and loop and random structures (67.0%). The alpha-helix content was predicted to be only 4.3%. The location of these secondary structures was assumed to be very similar to those of ascorbate oxidase and fungal laccase, the crystal structures of which have been determined.
Department of Chemistry, Faculty of Science, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
Kazutomo
K
Nitta
Kunishige
K
Kataoka
Takeshi
T
Sakurai
D000595:Amino Acid Sequence; D001483:Base Sequence; D003300:Copper / Q000737:chemistry*; D006801:Humans; D042845:Laccase; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry* / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry* / Q000145:classification / Q000235:genetics; D017433:Protein Structure, Secondary; D029045:Rhus / Q000201:enzymology*; D016415:Sequence Alignment; D014197:Trees
D010940:Plant Proteins; D003300:Copper; D010088:Oxidoreductases; D042845:Laccase