转移RNA（tRNA）是作为前体合成的，这些前体要求在5? 和3?端进修剪并对特定核苷酸进行一些修饰。Ribozyme RNase P普遍对处理tRNA的5?端负责。现在，与成熟苯基丙氨酸转移RNA 结合在一起的RNase P（来自Thermotoga maritima）的晶体结构已被确定。该结构显示了在pre-tRNA识别中所涉及的相互作用、活性点位置及催化中金属的作用。RNase P/tRNA核糖核蛋白结构也为一个基于RNA的古老世界是怎样演化为当今由蛋白-催化剂支配的世界的提供了线索。（生物谷Bioon.com）
Crystal structure of the T. maritima RNase P holoenzyme in complex with tRNA.
生物谷推荐原文出处：
Nature doi:10.1038/nature09516
Structure of a bacterial ribonuclease P holoenzyme in complex with tRNA
Nicholas J. Reiter,Amy Osterman,Alfredo Torres-Larios,Kerren K. Swinger,Tao Pan& Alfonso Mondragón
Ribonuclease (RNase) P is the universal ribozyme responsible for 5′-end tRNA processing. We report the crystal structure of the Thermotoga maritima RNase P holoenzyme in complex with tRNAPhe. The 154?kDa complex consists of a large catalytic RNA (P RNA), a small protein cofactor and a mature tRNA. The structure shows that RNA–RNA recognition occurs through shape complementarity, specific intermolecular contacts and base-pairing interactions. Soaks with a pre-tRNA 5′ leader sequence with and without metal help to identify the 5′ substrate path and potential catalytic metal ions. The protein binds on top of a universally conserved structural module in P RNA and interacts with the leader, but not with the mature tRNA. The active site is composed of phosphate backbone moieties, a universally conserved uridine nucleobase, and at least two catalytically important metal ions. The active site structure and conserved RNase P–tRNA contacts suggest a universal mechanism of catalysis by RNase P.
