Characterization of manganese peroxidases from the hyperlignolytic fungus IZU-154.
Four isozymes of manganese peroxidase (MnP) were identified in the culture fluid of the hyperlignolytic fungus IZU-154 under nitrogen starvation conditions. One of them was purified and characterized kinetically. The specific activity and Kcat/K(m) value of the MnP from IZU-154 were 1.6 times higher than those of the MnP from a typical lignin-degrading fungus, Phanerochaete chrysosporium. Two cDNAs encoding MnP isozymes from IZU-154 were isolated. The coding sequence of the two cDNAs, IZ-MnP1 cDNA and IZ-MnP2 cDNA, were 1,152 (384 amino acids) and 1,155 (385 amino acids) bp in length, respectively. They exhibit 96.2% identity at the nucleotide level and 95.1% identity at the amino acid level. Southern blot analysis indicated that two MnP isozyme genes exist in IZU-154 genomic DNA. The primary structures of two MnPs from IZU-154 were similar to those of MnPs from P. chrysosporium. The amino acid sequences including the important residues identified in MnPs from P. chrysosporium, such as the manganese-binding residues, the calcium-binding residues, the disulfide bonds, and the N-glycosylation site, were conserved in the two deduced IZ-MnPs. However, several discrepancies were found in the context around the distal histidine residue between MnP from IZU-154 and MnP from P. chrysosporium, which likely led to the difference in the kinetic parameters for MnP function.
Biotechnology Research Section, Bio-Technology Laboratory, Kobe Steel, Ltd., Japan.
M
M
Matsubara
J
J
Suzuki
T
T
Deguchi
M
M
Miura
Y
Y
Kitaoka
D000595:Amino Acid Sequence; D001483:Base Sequence; D001487:Basidiomycota / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008031:Lignin / Q000378:metabolism; D008969:Molecular Sequence Data; D010544:Peroxidases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D017931:DNA Primers; D018076:DNA, Complementary; D004271:DNA, Fungal; D007527:Isoenzymes; D008031:Lignin; D010544:Peroxidases; C051129:manganese peroxidase