Sprecher
Beschreibung
Coevolution of RNase P and the Ribosome
Anton S. Petrov (a,b*), Claudia Alvarez-Carreno (a,c), Loren Dean Williams (a,b), Mark A. Ditzler (d)
a NASA Center for the Origins of Life, Georgia Institute of Technology, Atlanta, GA, USA
b School of Chemistry and Biochemistry Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA, USA
c Department of Structural and Molecular Biology, University College London, London, United Kingdom
d Center for the Emergence of Life, NASA Ames Research Center, Moffett Field, California, USA
Translation is carried out by the most conserved assemblies in biology. Among these assemblies, the ribosome and RNase P are central players. These ancient ribonucleoprotein complexes achieved structural and functional maturity by the last universal common ancestor (LUCA) of life. In prior work, we reconstructed the evolutionary history of the ribosome using its three-dimensional structure, based on accretion and molecular fingerprints that date back to life's earliest stages. I will present an extension of our structural phylogenetic framework - based on the accretion model - to RNase P, a ribonucleoprotein responsible for processing pre-tRNAs. By sampling RNase P RNA (RPR) sequences and structures across phylogeny and partitioning them into RNA fragments based on insertion fingerprints, we characterized the state of RNase P at LUCA and reconstructed the chronology of its evolution. I will discuss how application of the accretion model requires correct secondary structures, and was successful for RPR only when the traditional secondary structure was corrected by reorganizing a pseudoknot. The chronology revealed that RNase P, like the ribosome, accreted modular RNA elements over evolution, while preserving the structure of pre-existing elements, thus maintaining a structural record. We used interactions with tRNA to link and unify the evolutionary trajectories of RPR and rRNA. These results support the view that RNase P and the ribosome co-evolved as part of a functionally integrated system. Finally, I will demonstrate that the ancestral catalytic sites of rRNA and RPR formed by the same process — the fusion of two stem-elbow-stem elements. The analysis of these two co-evolving RNAs also suggests that some of their accreted elements share common ancestry.