tRNA是以前体的形式被转录出来，具有未成熟的5'和3’末端，必须经过必要的加工才能成为有功能的分子。其中tRNA 5' 末端的加工由核酸内切酶RNase P来完成。作为体内保守的为生命活动所必需的一类生物大分子，有关RNase P的结构与催化机制的研究势必将加深拓展我们对体内基础的必需的生物学过程的理解。RNase P一共有两大类，一类是RNA-蛋白复合物由RNA介导催化反应，一类是仅由蛋白质组成的由蛋白质介导催化反应。过去的两年我们研究组在RNA介导的RNase P的结构与催化机理上取得了长足的进步和深刻的认识。在本项目中，我们将聚焦另一类仅由蛋白质组成的RNase P（PRORP）及其相关复合物，综合运用多种技术手段，在分子水平上探索PRORP发挥酶学活性的结构基础，探索PRORP的底物识别和催化机理，理清整个复合物亚基间的协同调控关系。

tRNA was transcribed as precursor molecules with immature 5' and 3’ end, which need to undergo necessary processing steps to be functional in translation. The removal of 5' leader sequence of pre-tRNA was carried out by an essential endonuclease RNase P. As an essential biological molecule that involved in so important a biological process, structural and catalytic mechanism studies of RNase P will definitely broad our understanding of the basic and essential process in living organism. RNase P can be categorize into two, one is RNA-based catalyst containing ribonucleoprotein complex, the other is protein-only enzymes (PRORP). In the past two years, our group made great progresses and gained a deep understanding of the structure and catalytic mechanism of the RNA-based eukaryotic RNase P. In this project , we will focus on the other RNase P category—PRORP. We will employ a combination of structural biology, molecular biology, biochemistry, and cell biology to study the.structural basis of the catalytic mechanism of PRORP, to investigate the substrate recognition and processing mechanism, and to clarify how each subunit in the complex coordinates together to achieve a full activity.