Mann Hagit, Ben-Asouli Yitzhak, Schein Aleks, Moussa Sana, Jarrous Nayef
Department of Molecular Biology, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
Mol Cell. 2003 Oct;12(4):925-35. doi: 10.1016/s1097-2765(03)00357-5.
Ribonuclease P (RNase P) is an essential enzyme that processes the 5' leader sequence of precursor tRNA. Eubacterial RNase P is an RNA enzyme, while its eukaryotic counterpart acts as catalytic ribonucleoprotein, consisting of RNA and numerous protein subunits. To study the latter form, we reconstitute human RNase P activity, demonstrating that the subunits H1 RNA, Rpp21, and Rpp29 are sufficient for 5' cleavage of precursor tRNA. The reconstituted RNase P precisely delineates its cleavage sites in various substrates and hydrolyzes the phosphodiester bond. Rpp21 and Rpp29 facilitate catalysis by H1 RNA, which seems to require a phylogenetically conserved pseudoknot structure for function. Unexpectedly, Rpp29 forms a catalytic complex with M1 RNA of E. coli RNase P. The results uncover the core components of eukaryotic RNase P, reveal its evolutionary origin in translation, and provide a paradigm for studying RNA-based catalysis by other nuclear and nucleolar ribonucleoprotein enzymes.
核糖核酸酶P（RNase P）是一种加工前体tRNA 5'前导序列的必需酶。细菌核糖核酸酶P是一种RNA酶，而其真核生物对应物则作为催化核糖核蛋白起作用，由RNA和众多蛋白质亚基组成。为了研究后一种形式，我们重建了人核糖核酸酶P的活性，证明亚基H1 RNA、Rpp21和Rpp29足以对前体tRNA进行5'切割。重建的核糖核酸酶P精确地确定了其在各种底物中的切割位点，并水解磷酸二酯键。Rpp21和Rpp29促进H1 RNA的催化作用，H1 RNA似乎需要一个系统发育上保守的假结结构来发挥功能。出乎意料的是，Rpp29与大肠杆菌核糖核酸酶P的M1 RNA形成催化复合物。这些结果揭示了真核核糖核酸酶P的核心成分，揭示了其在翻译中的进化起源，并为研究其他核和核仁核糖核蛋白酶基于RNA的催化作用提供了范例。
