InterPro domain: IPR036980

This entry includes p29 subunit (also known as Rpp29 or Pop4) of the Ribonuclease P complex [ 1 ]. Its homologues from eukaryotes are also a subunit of the RNase MRP complex. The structure of the RNase P subunit, Rpp29, from Methanobacterium thermoautotrophicum 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 [ 2 ]. Rpp29 ( 3.1.26.5 ) catalyses the endonucleolytic cleavage of RNA, removing 5'-extranucleotides from tRNA precursor. It interacts with the Rpp25 and Pop5 subunits.

Ribonuclease P (Rnp) is a ubiquitous ribozyme that catalyzes a Mg2 -dependent hydrolysis to remove the 5'-leader sequence of precursor tRNA (pre-tRNA) in all three domains of life [ 3 ]. In bacteria, the catalytic RNA (typically ~120kDa) is aided by a small protein cofactor (~14kDa) [ 4 ]. Archaeal and eukaryote RNase P consist of a single RNA and archaeal RNase P has four or five proteins, while eukaryotic RNase P consists of 9 or 10 proteins. Eukaryotic and archaeal RNase P RNAs cooperatively function with protein subunits in catalysis [ 5 ].

1. hPop4: a new protein subunit of the human RNase MRP and RNase P ribonucleoprotein complexes. Nucleic Acids Res. 27, 2465-72
2. Structure of Mth11/Mth Rpp29, an essential protein subunit of archaeal and eukaryotic RNase P. Proc. Natl. Acad. Sci. U.S.A. 100, 15398-403
3. The nucleotide sequence of chromosome I from Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. U.S.A. 92, 3809-13
4. Chance and necessity in the evolution of RNase P. RNA 24, 1-5
5. Rpp14 and Rpp29, two protein subunits of human ribonuclease P. RNA 5, 153-7