This entry contains one of the subunits, Rpp29, of RNase P. The structure of the RNase P subunit, Rpp29, from Methanothermobacter thermoautotrophicus has been determined. Mth Rpp29 is a member of the oligonucleotide/oligosaccharide binding fold family. It contains a structured beta-barrel core and unstructured N- and C-terminal extensions bearing several highly conserved amino acid residues that could be involved in RNA contacts in the protein-RNA complex .
RNase P is a ubiquitous ribonucleoprotein enzyme primarily responsible for cleaving the 5' leader sequence during maturation of tRNAs in all three domains of life. In eubacteria, this enzyme is made up of two subunits: a large RNA (approximately 120 kDa) responsible for mediating catalysis, and a small protein cofactor (approximately 15 kDa) that modulates substrate recognition and is required for efficient in vivo catalysis. In contrast, multiple proteins are associated with eukaryotic and archaeal RNase P, and these proteins exhibit no recognizable homology to the conserved bacterial protein subunit. In reconstitution experiments with recombinantly expressed and purified protein subunits Mth Rpp29, a homologue of the Rpp29 protein subunit from eukaryotic RNase P, is an essential protein component of the archaeal holoenzyme .