UGT2B7野生型及两个突变体的二聚体形成机理和对代谢活性影响的研究

UGT2B7是一种重要的二相代谢酶，能催化许多内源性信号分子、药物和致癌物的代谢，其中UGT2B7*71S和UGT2B7*2突变体在中国人群中发生频率较高，且与膀胱癌的发生有高相关性。我们的体外研究发现，两个突变体与UGT2B7*1相比其酶活性具有显著的差异。由于蛋白-蛋白相互作用（PPI）是导致蛋白质功能改变的机理之一，也是目前的研究热点，因此，在前期工作的基础上，本课题通过分子生物学方法获得野生型-野生型、野生型-变异体和同源及异源变异体-变异体共表达的重组酶，应用免疫共沉淀、荧光共振能量转移等方法,阐明UGT2B7*1和两个突变体能否形成同源和异源二聚体及其形成的机理；并且通过研究分析异源与同源二聚体的酶动力学行为与功能差异，明确第71位和第268位氨基酸位点对于UGT2B7二聚体的形成和底物选择性的关键作用。从而在分子水平上为指导UGT2B7底物个体化给药提供科学依据。

UDP-glucuronosyltransferase(UGT) 2B7 is an important drug phase II enzyme. It is responsible for gulcuronidation of many human endogenous signalling molecules, drugs and carcinogens. It's reported that mutants UGT2B7*71S and UGT2B7*2 have a higher occurrence frequency in Chinese population and is closely related to bladder cancer. Our in vitro study found that the catalytic activity between UGT2B7*71S or UGT2B7*2 and UGT2B7*1 was obviously different.For protein-protein interaction(PPI) is one of the mechanisms leading to enzyme function changes, we focus on this current research hotspot. Based on previous knowledge, we start with PPI to clarify the mechanism of forming homodimer and heterodimer by UGT2B7*1,UGT2B7*71S and UGT2B7*2, and the enzyme kinetics and function differences between these complexes. Our subject is to indentify the role of residue 71 and 268 in the dimer formation, whether mutants affect dimer stability and substrates binding. By investigating the change of catalytic activity on molecule level, we will provide UGT2B7 metablolic information for individual administration and clinical rational drug use.