富亮氨酸重复序列的预测、分类及配体识别的结构机制研究

Leucine-rich repeat (LRR) proteins participate in protein-protein interactions that are involved in a number of biologically important processes, such as cell adhesion, signal transduction, platelet aggregation, extracellular matrix assembly, neural development, DNA repair, pathogen invasion and immune response of hosts. However, the current LRR classification system is out of date and the ligand binding mechanisms of most LRR proteins are unclear. In this project, a new classification system of LRRs will be established and novel prediction-classification tools on LRR sequences will be developed based on our previously published two databases of LRR proteins. Moreover, in order to detect the structural distinctions between binding and non-binding LRR units, we will use bioinformatic approaches to comparatively analyze more than 1600 LRRs extracted from all LRR proteins with known crystal structures on three levels: sequence level, secondary structure level and three-dimensional level. The resulting tools and criteria will then be used to predict the ligand binding sites of Toll-like receptors 7/8. Site-directed mutagenesis experiments will be performed to verify our predictions. Our results will provide important clues for designing agonists and antagonists for LRR proteins (receptors) and help to develop immune-based therapeutic interventions for related diseases.

富亮氨酸重复序列（LRR）蛋白质在细胞黏连、信号传导、血小板凝聚、细胞外基质聚集、神经系统发育、DNA修复、病原入侵及免疫应答等重要过程中起关键性作用，与诸多人类疾病紧密相关。然而，目前LRR的分类体系陈旧，绝大多数LRR蛋白质与配体结合的结构机制未知。本项目将基于申请人前期发表的两个LRR蛋白质结构数据库，建立新的LRR分类体系，开发LRR序列的预测及分类软件，并使用生物信息学方法对所有已知晶体结构的LRR蛋白质中所含有的1600多个LRR单位进行序列水平、二级结构水平及三维结构水平的比较分析，从而发现结合性LRR区别于非结合性LRR的结构特异性，用以预测LRR蛋白质的功能位点。之后，将预测Toll样受体7/8的LRR域的配体结合位点，并以定点突变实验验证预测结果。研究结果将对LRR受体蛋白的拮抗剂与增效剂的设计以及相关疾病的免疫干预治疗法的开发具有重要指导意义。

富亮氨酸重复序列（LRR）蛋白质在细胞黏连、信号传导、血小板凝聚、细胞外基质聚集、神经系统发育、DNA修复、病原入侵及免疫应答等重要过程中起关键性作用，与诸多人类疾病紧密相关。此前LRR的分类体系陈旧，绝大多数LRR蛋白质与配体结合的结构机制未知。本项目基于申请人前期发表的两个LRR蛋白质结构数据库，建立了新的LRR分类体系，并开发LRR序列的预测及分类软件，并使用生物信息学方法对所有已知晶体结构的LRR蛋白质中所含有的1600多个LRR单位进行序列水平、二级结构水平及三维结构水平的比较分析，从而发现了结合性LRR区别于非结合性LRR的结构特异性。此外，本研究预测了Toll样受体7/8的LRR域的配体结合位点，并以定点突变实验验证预测结果。研究结果对LRR受体蛋白的拮抗剂与增效剂的设计以及相关疾病的免疫干预治疗法的开发具有重要指导意义。