Structure and mechanistic features of the prokaryotic minimal RNase P

eLife

Florian Altegoer¹  Pietro Ivan Giammarinaro¹  Georg Hochberg²  Gert Bange²  Simone Prinz³  Nadine B Waeber⁴  Rebecca Feyh⁴  Roland K Hartmann⁴ 

[1] Center for Synthetic Microbiology and Department of Chemistry, Philipps-University Marburg, Marburg, Germany;Center for Synthetic Microbiology and Department of Chemistry, Philipps-University Marburg, Marburg, Germany;Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany;Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany;Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany;

关键词: aquifex aeolicus rnase p;    HARP;    cryo-EM;    mass photometry;    E. coli;    Other;   

DOI  :  10.7554/eLife.70160

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Endonucleolytic removal of 5’-leader sequences from tRNA precursor transcripts (pre-tRNAs) by ribonuclease P (RNase P) is essential for protein synthesis. Beyond RNA-based RNase P enzymes, protein-only versions of the enzyme exert this function in various eukarya (there termed PRORPs) and in some bacteria (Aquifex aeolicus and close relatives); both enzyme types belong to distinct subgroups of the PIN domain metallonuclease superfamily. Homologs of Aquifex RNase P (HARPs) are also expressed in some other bacteria and many archaea, where they coexist with RNA-based RNase P and do not represent the main RNase P activity. Here, we solved the structure of the bacterial HARP from Halorhodospira halophila by cryo-electron microscopy, revealing a novel screw-like dodecameric assembly. Biochemical experiments demonstrate that oligomerization is required for RNase P activity of HARPs. We propose that the tRNA substrate binds to an extended spike-helix (SH) domain that protrudes from the screw-like assembly to position the 5’-end in close proximity to the active site of the neighboring dimer. The structure suggests that eukaryotic PRORPs and prokaryotic HARPs recognize the same structural elements of pre-tRNAs (tRNA elbow region and cleavage site). Our analysis thus delivers the structural and mechanistic basis for pre-tRNA processing by the prokaryotic HARP system.

【 授权许可】

CC BY