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The ancient history of the structure of ribonuclease P and the early origins of Archaea

DOI: 10.1186/1471-2105-11-153

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To study the evolution of this complex, we constructed rooted phylogenetic trees of RPR molecules and substructures and estimated RPP age using a cladistic method that embeds structure directly into phylogenetic analysis. The general approach was used previously to study the evolution of tRNA, SINE RNA and 5S rRNA, the origins of metabolism, and the evolution and complexity of the protein world, and revealed here remarkable evolutionary patterns. Trees of molecules uncovered the tripartite nature of life and the early origin of archaeal RPRs. Trees of substructures showed molecules originated in stem P12 and were accessorized with a catalytic P1-P4 core structure before the first substructure was lost in Archaea. This core currently interacts with RPPs and ancient segments of the tRNA molecule. Finally, a census of protein domain structure in hundreds of genomes established RPPs appeared after the rise of metabolic enzymes at the onset of the protein world.The study provides a detailed account of the history and early diversification of a fundamental ribonucleoprotein and offers further evidence in support of the existence of a tripartite organismal world that originated by the segregation of archaeal lineages from an ancient community of primordial organisms.With few exceptions [1], ribonuclease P (RNase P) is one of two universal ribozymes (the other is the ribosome) that are present in all living organisms. This ribonucleoprotein is generally composed of an RNA subunit, the RNase P RNA (RPR), and one or more protein subunits, the RNase P proteins (RPPs) [2]. RNase P functions as a phosphodiesterase carrying out the 5' endonucleolytic cleavage of transfer RNA (tRNA) precursor transcripts (pre-tRNA) to form mature functional tRNAs [3-5]. Regions of the RPR that contribute to the recognition of the substrate cleavage sites [the tRNA pseudouridine (TΨC) loop and CCA tail] are well studied. Remarkably, the catalytic function can be conducted by the RNA subunit indepen

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