Roles of protein subunits in RNA–protein complexes: Lessons from ribonuclease P

The RNR motif of B. subtilis RNase P protein interacts with both PRNA and pre-tRNA to stabilize an active conformer

“…1A). Although the RNA component alone is capable of catalyzing pre-tRNA cleavage in high salt in vitro, the protein is essential for catalytic activity in vivo (Hsieh et al 2004;Evans et al 2006;Gossringer et al 2006;Smith et al 2007). In vitro studies indicate that the P protein subunit contributes to numerous facets of RNase P catalysis including substrate and metal affinity and cleavage efficiency (Reich et al 1988;Crary et al 1998;Kurz et al 1998;Sun et al 2006).…”

Crystal Structure and Functional Analysis of an Archaeal Chromatin Protein Alba from the Hyperthermophilic ArchaeonPyrococcus horikoshiiOT3

“…11,12) Although the functionality of RNase P is similar from bacteria to humans, the chemical composition of this ribozyme differs in three phylogenetic domains of life: eubacteria, archaea, and eukarya. 13) Eubacterial RNase P is composed of a catalytic RNA and a single protein subunit, 14) while eukaryotic RNase Ps comprise a single RNA moiety and as many as 10 proteins; a highly purified nuclear RNase P from HeLa cells has at least 10 distinct protein subunits, termed Rpp14, Rpp20, Rpp21, Rpp25, Rpp29, Rpp30, Rpp38, Rpp40, hPop1, and hPop5. [15][16][17] Although Rpp21 and Rpp29 are known to be strongly involved in the catalytic activity of human RNase P, 18) the functional roles of other human RNase P proteins in RNase P have not been established.…”

Role of the snRNAs in spliceosomal active site

“…Using a mutant U2 snRNA which could only participate in the splicing of a substrates, to independently forming part of the active site and direct involvement in catalysis. 62 As a first step toward defining the share of the spliceosomal RNA and protein components in the formation of the active site and catalysis, the most direct and fruitful approach is likely the analysis of the function of snRNAs and proteins in isolation using simplified, in vitro models.…”

“…62,73 Assuming that the spliceosome is an RNA enzyme, the spliceosomal snRNAs are unusual ribozymes in many respects, perhaps most importantly, they are unusually small for a ribozyme catalyzing phosphodiester bond cleavage via the activation of a non-adjacent nucleophile. The other known natural ribozymes catalyzing such reactions, namely, group I and II introns and RNase P, are at least two and in many cases several folds longer than the combined length of human U6 and U2 snRNAs.…”