2004 Fiscal Year Final Research Report Summary
GENE AND FUNCTIONAL DIVERSITY OF CYTOCHROME P450 MOLECULAR SPECIES IN THE LIGNIN-DEGRADING BASIDIOMYCETE
| Project/Area Number |
15380224
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Boundary agriculture
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
WARIISHI Hiroyuki Kyushu University, Faculty of Agriculture, Professor, 大学院・農学研究院, 教授 (50253513)
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| Co-Investigator(Kenkyū-buntansha) |
TASHIRO Kosuke Kyushu University, Faculty of Agriculture, Associate Professor, 大学院・農学研究院, 助教授 (00192170)
KITAMOTO Yutaka Tottori Uriversity, Faculty of Agriculture, Professor, 農学部, 教授 (10032294)
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| Project Period (FY) |
2003 – 2004
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| Keywords | White-rot basidiomycetes / Metabolism of Aromatic Compounds / Lignin Degradation / Cytochrome P450 / Gene Diversity / Functional Diversity / Microexon / Substrate Recognition Site |
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| Research Abstract |
White-rot basidiomycetes are only known organism to be capable of degrading lignin. Lignin is the most abundant, renewable aromatic polymer and is known as one of the most recalcitrant biomaterials on the earth. Initially, fungi extracellularly attack polymeric lignin utilizing nonspecific oxidative enzymes, such as lignin and manganese peroxidases, resulting in the formation of a variety of aromatic fragments. One of the common features for these aromatic substrates is a high ionization potential ; thus extracellular oxidative enzymes could not initiate the metabolic reactions for certain substrates. The involvement of cytochrome P450(s) has been indicated for the degradation of recalcitrant aromatic compounds by white-rot fungi. Hydroxylation of aromatic moieties dramatically reduces their ionization potentials, forming more susceptible structures for further oxidative metabolism.
Recently, genome annotations of the white-rot basidiomycete, Phanerochaete chrysosporium, were almost completed by US DOE/JGI and the data were made available to the public (http://www.jgi.doe. gov/programs/whiterot.htm). Utilizing their annotation data and our cDNA cloning data, 154 cytochrome P450 genomic sequences were obtained. The gene diversity and the functional regulation of fungal P450s were studied via functional genomics, proteomics, homology modeling as well as conventional biochemical methods. From genomic studies, 122 Phanerochaete P450 genes were found to possess microexons (coding only 3-10 amino acids). Homology modeling indicated that these microexons play a role in diversifying the structure of substrate recognition sites. Metabolic and expression studies were successfully achieved to identify the function of 2 genes. A unique pathway crosstalk between P450 expressions, NADPH production, and heme biosynthesis were also found.
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Research Products
(16 results)
