Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.5 (RNase P)
 1,348 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DEAD-box proteins have been implicated in a wide array of cellular processes ranging from initiation of protein synthesis and ribosome biogenesis to mRNA splicing. Here, we report the isolation, biochemical characterization and crystallization of the first thermophilic DEAD box protein, Hera (heat-resistant RNA-dependent ATPase) from Thermus thermophilus HB8. The molecular mass of the deduced Hera protein sequence (510 amino acid residues) is 55.95 kDa. Hera possesses all of the conserved motifs found among the, DEAD-box RNA helicases. In addition, it also has a motif characteristic of the protein component of ribonuclease P at its C-terminal region (residues 372-386). Hera appears to be non-specific with respect to the RNA species that triggers ATPase activity. Nevertheless, at high temperature, ATPase activity is at a maximum when bacterial 16 S rRNA or 23 S rRNA are used as the substrates. Moreover, a deletion of the RNase P protein motif significantly reduces the ability of Hera to hydrolyze ATP in the presence of RNase P RNA. Hera has a specific ATPase activity of 480 units/microg and therefore, displays the highest ATPase specific activity reported for a protein of the RNA helicase family. We determined that Hera shows helix-destabilizing activity, and that the RNA-unwinding or helix-destabilizing activity of Hera is coupled to ATP hydrolysis. Since Hera is a stable thermophilic protein and we have obtained crystals of it diffracting beyond 2.6 A, the possibilities for structure determination of a full-length RNA-helicase are open.
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PMID:Hera from Thermus thermophilus: the first thermostable DEAD-box helicase with an RNase P protein motif. 1061 Jul 97

Human nuclear RNase P purified from HeLa cells has ATPase activity. This activity is associated with one of the protein subunits of the enzyme, Rpp20. Thus, human nuclear RNase P, which contains several proteins and one essential RNA, has at least one other enzymatic activity in addition to cleavage of phosphoester bonds in RNA. The amino acid sequence of Rpp20 has a signature motif found in an ATPase-containing subunit of a family of protein complexes (ABC transporters) that mediate a variety of trans-membrane traffic, as well as a segment, DIxxN, that resembles the DEAD box motif of many ATPases: together, these might represent an ATPase signature motif.
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PMID:A subunit of human nuclear RNase P has ATPase activity. 1114 58

The RPM2 gene of Saccharomyces cerevisiae codes for a protein subunit of mitochondrial RNase P and has another unknown essential function. We previously demonstrated that Rpm2p localizes to the nucleus and acts as a transcriptional activator. Rpm2p influences the level of mRNAs that encode components of the mitochondrial import apparatus and essential mitochondrial chaperones. Evidence is presented here that Rpm2p interacts with Dcp2p, a subunit of mRNA decapping enzyme in the two-hybrid assay, and is enriched in cytoplasmic P bodies, the sites of mRNA degradation and storage in yeast and mammalian cells. When overexpressed, GFP-Rpm2p does not impact the number and size of P bodies; however, it prevents their disappearance when translation elongation is inhibited by cycloheximide. Proteasome mutants, ump1-2 and pre4-2, that bypass essential Rpm2p function, also stabilize P bodies. The stabilization of P bodies by Rpm2p may occur through reduced protein degradation since GFP-Rpm2p expressing cells have lower levels of ubiquitin. Genetic analysis revealed that overexpression of Dhh1p (a DEAD box helicase localized to P bodies) suppresses temperature-sensitive growth of the rpm2-100 mutant. Overexpression of Pab1p (a poly (A)-binding protein) also suppresses rpm2-100, suggesting that Rpm2p functions in at least two aspects of mRNA metabolism. The results presented here, and the transcriptional activation function demonstrated earlier, implicate Rpm2p as a coordinator of transcription and mRNA storage/decay in P bodies.
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PMID:Rpm2p, a protein subunit of mitochondrial RNase P, physically and genetically interacts with cytoplasmic processing bodies. 1726 5

DEAD box helicases use the energy of ATP hydrolysis to remodel RNA structures or RNA/protein complexes. They share a common helicase core with conserved signature motifs, and additional domains may confer substrate specificity. Identification of a specific substrate is crucial towards understanding the physiological role of a helicase. RNA binding and ATPase stimulation are necessary, but not sufficient criteria for a bona fide helicase substrate. Here, we report single molecule FRET experiments that identify fragments of the 23S rRNA comprising hairpin 92 and RNase P RNA as substrates for the Thermus thermophilus DEAD box helicase Hera. Both substrates induce a switch to the closed conformation of the helicase core and stimulate the intrinsic ATPase activity of Hera. Binding of these RNAs is mediated by the Hera C-terminal domain, but does not require a previously proposed putative RNase P motif within this domain. ATP-dependent unwinding of a short helix adjacent to hairpin 92 in the ribosomal RNA suggests a specific role for Hera in ribosome assembly, analogously to the Escherichia coli and Bacillus subtilis helicases DbpA and YxiN. In addition, the specificity of Hera for RNase P RNA may be required for RNase P RNA folding or RNase P assembly.
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PMID:The putative RNase P motif in the DEAD box helicase Hera is dispensable for efficient interaction with RNA and helicase activity. 1878 31

Recent studies show that nuclear RNase P is linked to chromatin structure and function. Thus, variants of this ribonucleoprotein (RNP) complex bind to chromatin of small noncoding RNA genes; integrate into initiation complexes of RNA polymerase (Pol) III; repress histone H3.3 nucleosome deposition; control tRNA and PIWI-interacting RNA (piRNA) gene clusters for genome defense; and respond to Werner syndrome helicase (WRN)-related replication stress and DNA double-strand breaks (DSBs). Likewise, the related RNase MRP and RMRP-TERT (telomerase reverse transcriptase) are implicated in RNA-dependent RNA polymerization for chromatin silencing, whereas the telomerase carries out RNA-dependent DNA polymerization for telomere lengthening. Remarkably, the four RNPs share several protein subunits, including two Alba-like chromatin proteins that possess DEAD-like and ATPase motifs found in chromatin modifiers and remodelers. Based on available data, RNase P and related RNPs act in transition processes of DNA to RNA and vice versa and connect these processes to genome preservation, including replication, DNA repair, and chromatin remodeling.
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PMID:Roles of RNase P and Its Subunits. 2869 48