Characterization of RNA-based and protein-only RNases P from bacteria encoding both enzyme types

• Published in: RNA (Cambridge) Vol. 29; no. 3; pp. 376 - 391
• Main Authors: Gößringer, Markus, Wäber, Nadine B, Wiegard, Jana C, Hartmann, Roland K
• Format: Journal Article
• Language: English
• Published: United States Cold Spring Harbor Laboratory Press 01.03.2023
• Subjects: Bacteria; Bacteria - genetics; Complementation; E coli; Enzymatic activity; Escherichia coli; Escherichia coli - metabolism; Proteins; Ribonuclease P; Ribonuclease P - metabolism; Ribonucleic acid; RNA; RNA, Bacterial - metabolism; RNA, Transfer - genetics; Transfer RNA; tRNA; fragmented RNase P RNA; RNA-based RNase P; bacterial RNase P; protein-only RNase P; HARP
• ISSN: 1355-8382; 1469-9001
• DOI: 10.1261/rna.079459.122

A small group of bacteria encode two types of RNase P, the classical ribonucleoprotein (RNP) RNase P as well as the protein-only RNase P HARP ( omolog of Nase ). We characterized the dual RNase P activities of five bacteria that belong to three different phyla. All five bacterial species encode functional RNA (gene ) and protein (gene ) subunits of RNP RNase P, but only the HARP of the thermophile (phylum Thermodesulfobacteria) was found to have robust tRNA 5'-end maturation activity in vitro and in vivo in an RNase P depletion strain. These findings suggest that both types of RNase P are able to contribute to the essential tRNA 5'-end maturation activity in , thus resembling the predicted evolutionary transition state in the progenitor of the Aquificaceae before the loss of and genes in this family of bacteria. Remarkably, RNase P RNA is transcribed with a P12 expansion segment that is posttranscriptionally excised in vivo, such that the major fraction of the RNA is fragmented and thereby truncated by ∼70 nt in the native host as well as in the complementation strain. Replacing the native P12 element of RNase P RNA with the short P12 helix of RNase P RNA abolished fragmentation, but simultaneously impaired complementation efficiency in cells, suggesting that intracellular fragmentation and truncation of RNase P RNA may be beneficial to RNA folding and/or enzymatic activity.