LIGNIN BIODEGRADATON--LIGNINASE & GLUCOSE OXIDASE GENES

木质素生物降解剂--木质素酶

• 批准号: 3295807
• 负责人: CA A REDDY
• 金额: $ 8.01万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-07-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3295807
• 关键词: Basidiomycetes; biotransformation; detoxification; environmental toxicology; fungal genetics; gene expression; genetic library; genetic mapping; genetic transcription; glucose oxidase; lignin; molecular cloning; nucleic acid sequence; peroxidases; regulatory gene

Lignin is the second most abundant renewable organic polymer in the biosphere. Lignin biodegradation is of utmost importance in the earth's carbon cycle not only because of its great abundance but also because of its recalcitrance. Phanerochaete chrysosporium, a filamentous ligninolytic basidiomycete, produces H202-generating glucose oxidase and H202 dependent extracellular heme peroxidases called ligninases, but only during idioptase (secondary metabolism). Ligninases constitute a class of six or more related proteins that appear to be encoded by different genes. There has been much recent interest in ligninases because these proteins, in addition to their involvement in degradation of lignin, also play a key role in the detoxification of recalcitrant environmental pollutants such as dioxins, DDT, lindane and benzopyrenes, which constitute a serious public health hazard. Our long term objective is to isolate and characterize various lignin degradation genes from P. chrysosporium and study the molecular organization, expression and regulation of these genes. In this study, we propose to characterize ligninase genomic clones including construction of detailed restriction maps, determine the presence and nature of introns, determination of gene boundaries, and DNA sequence determination of the 5' upstream region (approximately 1 kb) and the entire coding region. Upstream regulatory regions will be identified using DNase I protection analysis. Transcription specific binding proteins, if any present, will be isolated and characterized. Furthermore, chromosome organization of P. chrysosporium and distribution of ligninase genes in the chromosome(s) will be determined. In this study, we also propose to isolate and characterize cDNA and genomic clones for glucose oxidase, another enzyme expressed during secondary metabolism and is reported to be associated with the lignin degradation system. The cDNA and genomic clones for glucose oxidase will be characterized the same way as proposed for the ligninase clones. The results of the proposed research will not only aid in the understanding of gene structure and organization in P. chrysosporium but also will make an important fundamental contribution to the knowledge base on the biology and genetics of filamentous fungi. The data obtained will additionally be useful in producing genetically engineered strains of P. chrysosporium that give high yields of ligninase, an enzyme with many important practical applications.

木质素是世界上第二丰富的可再生有机聚合物。 生物圈 木质素的生物降解在生物降解中至关重要。 地球的碳循环不仅是因为其丰富的 也是因为它的不确定性。 平革 chrysosporium是一种丝状木质素分解担子菌， 产生H2O2的葡萄糖氧化酶和H2O2依赖性葡萄糖氧化酶 细胞外血红素过氧化物酶称为木质素酶，但只有在 Idioptase（次级代谢）。 木质素酶构成一类 六种或更多相关蛋白质， 不同的基因 最近人们对 木质素酶，因为这些蛋白质，除了它们的参与， 在降解木质素方面，也起着关键的解毒作用 有害的环境污染物，如二恶英，滴滴涕， 林丹和苯并芘，这构成了严重的公共卫生 隐患有 我们的长期目标是分离和表征 黄孢原毛平革菌木质素降解基因及其研究 它们的分子组织、表达和调节 基因. 在这项研究中，我们提出了表征木质素酶， 包括构建详细限制性内切酶的基因组克隆 图谱，确定内含子的存在和性质， 基因边界和DNA序列的确定 确定5'上游区域（约1kb），和 整个编码区。 上游监管区域将 使用DNase I保护分析鉴定。 转录 将分离特异性结合蛋白（如果存在）， 表征了 此外，还研究了P. 木质素酶基因在黄孢霉中的分布 将确定染色体。 在这项研究中，我们还建议 分离和鉴定葡萄糖的cDNA和基因组克隆， 氧化酶，另一种在次级代谢过程中表达的酶 据报道与木质素降解有关 系统 葡萄糖氧化酶的cDNA和基因组克隆将在 以与针对木质素酶克隆提出的相同的方式进行表征。 拟议研究的结果不仅有助于 了解P. 也将成为一个重要的基础 生物学和遗传学知识库的贡献 丝状真菌 所获得的数据还将有助于 产生基因工程的黄孢原毛平革菌菌株， 产生高产量的木质素酶，一种具有许多重要功能的酶， 实际应用等