红球菌P14降解雌酮途径中新型单加氧酶CYP123A9作用机制的研究

细胞色素P450单加氧酶（CYP450）是一种重要的降解有机污染物的含血红素蛋白，能够催化底物发生羟基化，从而起始降解。然而，目前还没有研究发现细菌来源CYP450在雌激素降解过程中的作用。申请人前期研究发现，海洋红球菌P14中的细胞色素P450单加氧酶CYP123A9可能参与雌酮的降解。基于此，本研究拟利用RT-qPCR、基因敲除和回补及检测酶转化产物来验证CYP123A9降解雌酮的功能；通过分析活性中心、底物结合位点、蛋白结构和功能之间的关系，探索CYP123A9羟化过程的分子机理。预期结果将阐明单加氧酶CYP123A9催化雌酮的作用机制，为系统揭示红球菌P14降解雌酮的分子机制提供依据。

Cytochrome P450 monooxygenase (CYP450) is an important heme-containing protein which degrade organic pollutants and has the ability to catalyze the hydroxylation of substrate. Thus the hydroxylation by CYP450 is considered mainly as a prelude to catabolism. However, the role of the bacterial CYP450 during biodegradation of estrone has not been reported. In our previous studies, we found that CYP123A9 in Rhodococcus sp. P14 may initiate the degradation of estrone. Based on this, by the use of RT-qPCR, gene knockout, genetic complementation test, and detection of degradation products, this project intends to verify the role of CYP123A9 during estrone degradation by strain P14. Next, we analyze the substrate binding site, the catalytic reaction mechanism and the relationship between the enzyme structure to explore the mechanism of the functional enzyme CYP123A9. This study will reveal the catalytic mechanism of monooxygenase CYP123A9 and the molecular mechanism of degrading estrone by strain P14.