人胰岛素调节的氨基肽酶IRAP的结构与功能研究

Screening targeted drugs based on the protease structure has become a research hotspot. It has been found that the aminopeptidase IRAP (insulin regulated aminopeptidase) constructively expressed on human cells, can be used as the angiotensin IV (AT4) receptor to improve cognitive ability; can be involved in epitope formation and starting antigen presentation; can assitant glucose transporter-4 translocation to the cell membrane and be associated with type II diabetes. Screening specific drugs targeted to IRAP, will provide new possibilities for the treatment of these diseases. However, due to the current understanding of the structure of IRAP is just based on the computer modeling using the similar aminopeptidases, which making drug design just stay at the level of the analog AT4 structure. We have resolved the crystal structure of some peptidase: APN, APA and the ACE2 and analysised the enzyme mechanism of the aminopeptidase those structure had been resolved. In this project, we have purified the protein of IRAP,and then we will resolve the crystals structure of IRAP and it's mutant protein, IRAP + inhibitors/aminoacids, IRAP mutant protein+substrates complexes, and analysis the mechanism of enzyme specificility and the interaction with other proteins/peptides, to explain the physiological and pathological functions of IRAP. Our project will provide the structure basics for designing and screening high specificity and high affinity drugs targeted to IRAP, as well as providing a reference for study the interactions of other proteases with their substrates.

胰岛素调节的氨基肽酶（IRAP）在机体中组成性表达，可作为血管紧张素IV（AT4）的受体，参与记忆和认知；辅助葡萄糖转运蛋白-4从内体向胞膜转位，与II型糖尿病发病相关。筛选IRAP靶向药物，将为治疗相关疾病提供新的可能。但由于IRAP的晶体结构尚未发布，其靶向药物的设计仅停留在模拟AT4的阶段。本实验室已解析出同类肽酶APN、APA和ACE2及其复合物的结构，分析了结构已知的多种氨基肽酶的酶学机制，并设计了APN靶向抗癌药物，已在动物实验中取得明显疗效。我们拟在已纯化出IRAP蛋白的基础上，进一步解析IRAP及其与底物/抑制剂复合物的晶体结构，结合酶动力学检测，对比分析IRAP酶特异性的发生机制及与多肽相互作用的方式。本项目将进一步解释IRAP的生理、病理功能，启动IRAP靶向药物的计算机虚拟扫描研究，提高新药筛选效率、降低筛选成本，同时也为其他蛋白酶的结构和功能研究提供借鉴。