Fluorogenic多肽探针是和靶标作用时能产生荧光或荧光增强现象的识别分子，具有特异性好、亲和力高、免洗等优点，在蛋白质检测领域应用广泛。多肽展示技术是筛选fluorogenic多肽的有效方法之一，可以克服理性设计依赖天然存在的多肽配体或底物的限制，但多数筛选出来的多肽和蛋白结合后荧光不增强。本项目拟将mRNA展示技术与流式分选技术相结合，以受体蛋白PDGFRA胞外段为模型，开展fluorogenic多肽探针筛选新方法研究。研究内容包括：1）构建一个环境敏感型荧光基团4-DMN修饰的mRNA展示多肽文库；2）分别以BaF3-PDGFRA细胞和磁珠固定的PDGFRA为模型靶标，利用流式分选出靶向PDGFRA的多肽探针。测量目标多肽和蛋白结合的亲和力以及结合后荧光变化情况。通过对比新方法和现有方法，得出各种方法的优缺点，为建立一种高效筛选fluorogenic多肽探针的新方法提供实验基础。

Fluorogenic peptides are molecules that can generate or enhance fluorescence when interacting with target and are widely used in protein detection field due to their specificity, high affinity and wash-free properties. Peptide display technologies are effective tools for screening fluorogenic peptides and could overcome limits of rational design that rely on natural existing peptide ligand or peptide substrate. However, in most case, selected peptides do not increase fluorescence intensity upon target recognition. Therefore, we propose to use PDGFRA as the model target to study new selection strategies that integrate mRNA display and fluorescence-activated cell sorting. This research will include: 1)Generate an environment sensitive fluorophore 4-DMN modified peptide library; 2)Select peptide probes that specifically bind to PGFDRA using cells and magnetic immobilized protein as target, respectively. Determine the dissociation constant of selected peptides against to PDGFRA, measure fluorescence intensity change of the selected peptides upon binding to PDGFRA. Compare the advantages and disadvantages of the new methods and existing method and hopefully this will pave the way for developing a novel selection method for screening fluorogenic peptides.