This family consists of several archaeal and eukaryotic proteins. The archaeal proteins are found to be expressed within ribosomal operons and several of the sequences are described as ribonuclease P protein subunit p29 proteins [1,2]. 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 catalyses the endonucleolytic cleavage of RNA, removing 5'-extranucleotides from tRNA precursor. It interacts with the Rpp25 and Pop5 subunits.

1: hPop4: a new protein subunit of the human RNase MRP and RNase P ribonucleoprotein complexes. van Eenennaam H, Pruijn GJ, van Venrooij WJ; Nucleic Acids Res. 1999;27:2465-2472. PMID:10352175

2: Structure of Mth11/Mth Rpp29, an essential protein subunit of archaeal and eukaryotic RNase P. Boomershine WP, McElroy CA, Tsai HY, Wilson RC, Gopalan V, Foster MP; Proc Natl Acad Sci U S A. 2003;100:15398-15403. PMID:14673079