单加氧酶可催化天然产物生物合成中多种类型的氧化反应，是天然产物结构多样性和复杂性的重要来源，但未有从单加氧酶mRNA可变剪切水平上解析其独特酶学催化功能与机制。本课题研究丝状真菌齿梗孢霉中单加氧酶AurC三个可变剪切异构体在aurovertins生物合成不同阶段高效有序环氧化、羟化的催化功能；通过蛋白晶体结构解析三个异构体蛋白对结构类似底物的特异识别机制，及其高效催化的分子机制；同时基于aurC可变剪切，对aurovertins结构类似物citreoviridin生物合成中单加氧酶同源基因ctvC进行人工可变剪切改造，获得CtvC异构体酶来进一步氧化citreoviridin来生产新化合物。本课题首次揭示可变剪切导致的酶功能多样性和特异性在天然产物生物合成中的精确性和高效性催化机制，并为通过合成生物学理念从可变剪切水平上人工改造修饰酶来获得更多复杂多样天然产物奠定基础。

Though various types of oxidations catalyzed by monooxygenases for biosynthesis of natural products are vital to their structural diversity and complexity, there is no report on the level of mRNA alternative splicing of monooxygenases for their unique enzymatic functions and catalytic mechanisms. Here we will study the efficient epoxidation and hydroxylation catalyzed by three alternatively spliced isoforms of AurC during biosynthesis of aurovertins in the filamentous fungus Calcarisporium arbuscula, and reveal the mechanisms of specific recognition and efficient catalysis by three isoforms on the structurally similar substrates by protein crystallization. Moreover, ctvC, which is the homologous gene for biosynthesis of citreoviridin, the analogs of aurovertins, is artificially engineered by alternative splicing manually based on aurC, to obtain the corresponding CtvC isoforms to further oxidize citreoviridin for new products. Our work will for the first time unveil the mechanisms of highly precise and efficient biosynthesis of natural products because of the enzyme function diversity and specificity, which results from the mRNA alternative splicing, and also provide the basis for biosynthesis of structurally more complex and diverse natural products by manual engineering of tailoring enzymes based on alternative splicing from the point view of synthetic biology.