Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.26.5 (RNase P)
1,348 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ribonuclease P (RNase P) RNA genes of LL-2,6-diaminopimelic acid (LL-A2pm)-containing actinomycetes, except Streptomyces species, were sequenced after PCR-amplification and cloning. By using the sequence data, the relationships between species within genera and the relationships between taxa above genus level were investigated and the usefulness of the RNase P RNA gene as another phylogenetic marker was evaluated. RNase P RNA gene sequences of all strains used in this study contained relatively conserved regions along with highly variable regions. The mean RNase P RNA gene similarity value was approximately 82 +/- 18% and the mean RNase P RNA gene similarity value when gaps were included was approximately 76 +/- 24%. The nucleotide similarities between the RNase P RNA genes of different strains were mostly fewer than the 16S rDNA similarities. The RNase P RNA gene was more useful than 16S rDNA for clearly differentiating the relationships between species belonging to a genus and the relationships between some genera. However, nucleotide sequences of RNase P RNA genes were not necessarily appropriate for comparisons at all taxonomic levels (such as those between species, between genera and between families).
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PMID:Comparative sequence analyses of the ribonuclease P (RNase P) RNA genes from LL-2,6-diaminopimelic acid-containing actinomycetes. 1115 76

Ribonuclease P (RNase P) catalyzes the 5' maturation of precursor tRNA transcripts and, in bacteria, is composed of a catalytic RNA and a protein. We investigated the oligomerization state and the shape of the RNA alone and the holoenzyme of Bacillus subtilis RNase P in the absence of substrate by synchrotron small-angle X-ray scattering and affinity retention. The B. subtilis RNase P RNA alone is a monomer; however, the scattering profile changes upon the addition of monovalent ions, possibly suggesting different interdomain angles. To our surprise, the X-ray scattering data combined with the affinity retention results indicate that the holoenzyme contains two RNase P RNA and two RNase P protein molecules. We propose a structural model of the holoenzyme with a symmetrical arrangement of the two RNA subunits, consistent with the X-ray scattering results. This (P RNA)2(P protein)2 complex likely binds substrate differently than the conventional (P RNA)1(P protein)1 complex; therefore, the function of the B. subtilis RNase P holoenzyme may be more diverse than previously thought. These revisions to our knowledge of the RNase P holoenzyme suggest a more versatile role for proteins in ribonucleoprotein complexes.
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PMID:The Bacillus subtilis RNase P holoenzyme contains two RNase P RNA and two RNase P protein subunits. 1123 80

Ribonuclease P is an ancient enzyme that cleaves pre-tRNAs to generate mature 5' ends. It contains an essential RNA subunit in Bacteria, Archaea, and Eukarya, but the degree to which the RNA subunit relies on proteins to supplement catalysis is highly variable. The eukaryotic nuclear holoenzyme has recently been found to contain almost twenty times the protein content of the bacterial enzymes, in addition to having split into at least two related enzymes with distinct substrate specificity. In this review, recent progress in understanding the molecular architecture and functions of nuclear forms of RNase P will be considered.
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PMID:Eukaryotic ribonuclease P: increased complexity to cope with the nuclear pre-tRNA pathway. 1124 45

Ribonuclease P (RNase P) is the endoribonuclease responsible for the 5'-maturation of precursor tRNA transcripts. In bacteria, RNase P is composed of a catalytic RNA subunit and an associated protein subunit that enhances the substrate specificity of the holoenzyme. We have initiated a study of the biophysical properties of the protein subunit from Bacillus subtilis RNase P (P protein) toward the goal of understanding the thermodynamics of RNase P holoenzyme assembly. The P protein is predominantly unfolded in 10 mM sodium cacodylate at neutral pH based on circular dichroism and NMR studies and therefore has several characteristics typical of "intrinsically unstructured" proteins. Furthermore, the P protein folds to its native alpha/beta structure upon addition of various small molecule anions. Anion-induced folding is best attributed to the binding of these anions to the folded state of the protein, and a model is presented which describes the observed tightly coupled folding and binding phenomena. The P protein also undergoes a cooperative folding transition upon addition of the osmolyte trimethylamine N-oxide (TMAO). The equilibrium constant of folding (K(fold)) at 37 degrees C for the P protein was determined to be 0.0071 +/- 0.0005 using a two-state folding model to describe the TMAO titration data. Thus, the folding and binding equilibria observed in the anion-induced folding of the P protein can be uncoupled to determine the intrinsic binding affinities (K(a)'s) of the anionic ligands. Evidence that the osmolyte-induced and the ligand-induced folded conformations of the P protein are structurally similar is also presented.
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PMID:Linked folding and anion binding of the Bacillus subtilis ribonuclease P protein. 1125 88

It is demonstrated that acceptor stem duplexes derived from native tRNAs which contain a three-nucleotide extension at the 5'-terminus of mature tRNA are minimal substrates for ribonuclease P from both Escherichia coli and Bacillus subtilis. Variants with a cytidine at position -1 are most efficiently processed whereas the G -1 variant represents a comparatively poor substrate. An A -1 acceptor stem variant is a slightly better substrate than the G -1 variant though generally distinctly less efficient than the C -1 duplex. This is in qualitative agreement with the frequency of the occurrence of the corresponding nucleotides at position -1 in natural substrates, which is highest for pyrimidines and least for G. NMR analyses of the corresponding acceptor stems reveal that the conformation of the nucleotides at position -1 correlates with the substrate preferences of Ribonuclease P: Whereas C -1 adopts a conformation characterized by a glycosidic angle in the anti range (close to high-anti), the G -1 is clearly in syn conformation, and that of A -1 is intermediate between high-anti and syn. The riboses of nucleotides -1 are in all cases predominantly 2'-endo puckered.
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PMID:Correlation between processing efficiency for ribonuclease P minimal substrates and conformation of the nucleotide -1 at the cleavage position. 1125 57

Ribonuclease P (RNase P) is an essential enzyme that cleaves the 5' leader sequences of precursor tRNAs (pre-tRNAs) to generate mature tRNAs. The RNase P-like activity from Trypanosoma brucei mitochondria (mtRNase P) was purified over 10000-fold by sequential column chromatography. This is the first demonstration of such activity from mitochondria of parasitic protozoa. Its apparent molecular weight is approximately 70 kDa, considerably less than bacterial RNase P. Preliminary characterizations revealed no RNA component that is essential for this activity. Like other RNase P activities, the cleavage generates mature tRNAs with a terminal 5'-phosphate at the cleavage site and the 5' leader sequence with a 3'-hydroxyl. Disruption of the pre-tRNA tertiary structure inhibits the cleavage of the substrates. These data suggest that although all mitochondrial tRNAs are encoded in nuclear DNA in T. brucei, these cells contain an RNase P in the mitochondrion that cleaves the 5' terminal leader sequences of pre-tRNAs to generate mature tRNAs. Cleavage by mtRNase P of a pre-tRNA substrate that was divided into two fragments was demonstrated. This shows the feasibility of artificial regulation of gene expression that can be achieved by creating a complex made of target mRNA and a complementary small oligonucleotide that resembles natural substrates for RNase P.
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PMID:Mitochondrial ribonuclease P activity of Trypanosoma brucei. 1137 45

Ribonuclease P (RNase P) catalyzes the 5'-end maturation of transfer RNA molecules. Recent evidence suggests that the eukaryotic protein subunits may provide substrate-binding functions (True, H. L., and Celander, D. W. (1998) J. Biol. Chem. 273, 7193-7196). We now report that Pop3p, an essential protein subunit of the holoenzyme in Saccharomyces cerevisiae, displays novel RNA-binding properties. A recombinant form of Pop3p (H6Pop3p) displays a 3-fold greater affinity for binding pre-tRNA substrates relative to tRNA products. The recognition sequence for the H6Pop3p-substrate interaction in vitro was mapped to a 39-nucleotide long sequence that extends from position -21 to +18 surrounding the natural processing site in pre-tRNA substrates. H6Pop3p binds a variety of RNA molecules with high affinity (K(d) = 16-25 nm) and displays a preference for single-stranded RNAs. Removal or modification of basic C-terminal residues attenuates the RNA-binding properties displayed by the protein specifically for a pre-tRNA substrate. These studies support the model that eukaryotic RNase P proteins bind simultaneously to the RNA subunit and RNA substrate.
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PMID:Novel RNA-binding properties of Pop3p support a role for eukaryotic RNase P protein subunits in substrate recognition. 1152 78

Ribonuclease P, the ubiquitous endonuclease required for generating mature tRNA 5' ends, is a ribonucleoprotein in most organisms and organelles, with the exception of mitochondria and chloroplasts of multicellular organisms. The cyanelle of the primitive alga Cyanophora paradoxa is the only photosynthetic organelle where the ribonucleoprotein nature of this enzyme has been functionally proven. tmRNA is another highly structured RNA: it can be aminoacylated with alanine, which is then incorporated into a tag peptide encoded on the same RNA molecule. This dual-function RNA has been found in bacteria, and its gene is also present in mitochondria and plastids from primitive organisms. Since nothing is known about the expression of this RNA in organelles, we have performed processing studies and determined the promoter of cyanelle pre-tmRNA. This RNA is transcribed as a precursor molecule in vivo. Synthetic transcripts of cyanelle pre-tmRNA, including or lacking the mature 3' CCA-end, are efficiently and correctly processed in vitro by bacterial RNase P ribo- and holoenzymes and by the homologous cyanelle RNase P. In addition to these experimental data, we propose a novel secondary structure model for this organellar tmRNA, which renders it more similar to its bacterial counterpart.
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PMID:In vitro and in vivo processing of cyanelle tmRNA by RNase P. 1172 25

Ribonuclease P (RNase P) is a ubiquitous endoribonuclease that cleaves precursor tRNAs to generate mature 5' termini. Although RNase P from all kingdoms of life have been found to have essential RNA subunits, the number and size of the protein subunits ranges from one small protein in bacteria to at least nine proteins of up to 100 kDa. In Saccharomyces cerevisiae nuclear RNase P, the enzyme is composed of ten subunits: a single RNA and nine essential proteins. The spatial organization of these components within the enzyme is not yet understood. In this study we examine the likely binary protein-protein and protein-RNA subunit interactions by using directed two- and three-hybrid tests in yeast. Only two protein subunits, Pop1p and Pop4p, specifically bind the RNA subunit. Pop4p also interacted with seven of the other eight protein subunits. The remaining protein subunits all showed one or more specific protein-protein interactions with the other integral protein subunits. Of particular interest was the behavior of Rpr2p, the only protein subunit found in RNase P but not in the closely related enzyme, RNase MRP. Rpr2p interacts strongly with itself as well as with Pop4p. Similar interactions with self and Pop4p were also detected for Snm1p, the only unique protein subunit so far identified in RNase MRP. This observation is consistent with Snm1p and Rpr2p serving analogous functions in the two enzymes. This study provides a low-resolution map of the multisubunit architecture of the ribonucleoprotein enzyme, nuclear RNase P from S. cerevisiae.
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PMID:Interactions among the protein and RNA subunits of Saccharomyces cerevisiae nuclear RNase P. 1188 Jun 23

Ribonuclease P (RNase P) is an essential endonuclease that acts early in the tRNA biogenesis pathway. This enzyme catalyzes cleavage of the leader sequence of precursor tRNAs (pre-tRNAs), generating the mature 5' end of tRNAs. RNase P activities have been identified in Bacteria, Archaea, and Eucarya, as well as organelles. Most forms of RNase P are ribonucleoproteins, i.e., they consist of an essential RNA subunit and protein subunits, although the composition of the enzyme in mitochondria and chloroplasts is still under debate. The recent purification of the eukaryotic nuclear RNase P has demonstrated a significantly larger protein content compared to the bacterial enzyme. Moreover, emerging evidence suggests that the eukaryotic RNase P has evolved into at least two related nuclear enzymes with distinct functions, RNase P and RNase MRP. Here we review current information on RNase P, with emphasis on the composition, structure, and functions of the eukaryotic nuclear holoenzyme, and its relationship with RNase MRP.
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PMID:Eukaryotic ribonuclease P: a plurality of ribonucleoprotein enzymes. 1204 94


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