Structural insight into precursor tRNA processing by yeast ribonuclease P

Ribonuclease P (RNase P) is a universal ribozyme responsible for processing the 5'-leader of pre–transfer RNA (pre-tRNA). Here, we report the 3.5-angstrom cryo–electron microscopy structures of Saccharomyces cerevisiae RNase P alone and in complex with pre-tRNAPhe. The protein components form a hook-shaped architecture that wraps around the RNA and stabilizes RNase P into a "measuring device" with two fixed anchors that recognize the L-shaped pre-tRNA. A universally conserved uridine nucleobase and phosphate backbone in the catalytic center together with the scissile phosphate and the O3' leaving group of pre-tRNA jointly coordinate two catalytic magnesium ions. Binding of pre-tRNA induces a conformational change in the catalytic center that is required for catalysis. Moreover, simulation analysis suggests a two-metal-ion SN2 reaction pathway of pre-tRNA cleavage. These results not only reveal the architecture of yeast RNase P but also provide a molecular basis of how the 5'-leader of pre-tRNA is processed by eukaryotic RNase P.

Source: ScienceNOW - November 8, 2018 Category: Science Authors: Lan, P., Tan, M., Zhang, Y., Niu, S., Chen, J., Shi, S., Qiu, S., Wang, X., Peng, X., Cai, G., Cheng, H., Wu, J., Li, G., Lei, M. Tags: Biochemistry, Online Only r-articles Source Type: news