Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pathway is described for activation by Mg2+ of substrates for M1 RNA, the catalytic subunit of the RNase P from Escherichia coli. The dissociation constants are reported for binding of Mg2+ to the substrate and for the binding of the metal ion-substrate complex to the enzyme. The enzyme binds the substrate with the same affinity whether or not Mg2+ is already bound to the substate. However, only substrates with bound Mg2+ can make a productive ternary complex when combined with the enzyme. The presence of certain 2'-hydroxyl groups in the substrate is required to stabilize the binding of Mg2+ and, thereby, to increase the lifetime of the ternary complex. An energy profile for the reaction of M1 RNA with a small model substrate is presented and the role of Mg2+ bound to the substrate is discussed.
J Mol Biol 1993 Apr 05
PMID:Pathway of activation by magnesium ions of substrates for the catalytic subunit of RNase P from Escherichia coli. 768 57

Substrate specificity requirements of the plant mitochondrial RNase P were investigated with different natural and mutated substrates. Heterologous precursors with intact tRNAs from plant and fungal mitochondria, from bacteria, archaebacteria and of eukaryotic origins were processed faithfully, albeit with different efficiencies. Alteration of the acceptor stem length did not disturb correct processing, while activity is completely inhibited by deletion of the pseudouridine loop. Such and other minimal substrates processed by the E. coli RNase P are not recognized as substrates by the plant mitochondrial enzyme, suggesting different requirements for substrate recognition.
Biochem Mol Biol Int 1993 Mar
PMID:Plant mitochondrial RNase P and E. coli RNase P have different substrate specificities. 768 45

To investigate the function of the catalytic subunit of Escherichia coli RNase P, M1 RNA, we studied cleavage by different M1 RNA mutants of wild-type precursors to tRNA(TyrSu3), tRNA(His) and tRNA(SerSu1). We showed that deletion or substitution of the conserved nucleotides G291, G292, U294 and A295 in M1 RNA resulted in a shift of the cleavage site for the tRNA(SerSu1) precursor, whereas the other two tRNA precursors were cleaved at the normal position. By using chimeric tRNA precursors in which the acceptor-stem of the tRNA(TyrSu3) precursor was replaced by the acceptor-stem derived from the tRNA(SerSu1) precursor, we showed that the aberrant cleavage by M1 RNA mutants could be reversed by substituting the nucleotide at position -2 in one of the chimeric precursors. These results suggest, in support of our previous findings, that different tRNA precursors are processed differently and that the primary structure of the amino acid acceptor-stem of a tRNA precursor plays a significant role in the RNase P cleavage reaction. Furthermore, in agreement with a previous report, a truncated tRNA(TyrSu3) precursor was cleaved aberrantly by a mutant M1 RNA in which the nucleotide at position 92 had been deleted. In contrast, a corresponding truncated tRNA(SerSu1) precursor was cleaved at the same position both by the wild-type and by this mutant M1 RNA. We conclude that not only the primary structures of the acceptor-stems of tRNA precursors, but also the primary structures in different regions of M1 RNA determine the location of the cleavage site on various tRNA precursors. Here we have identified the region G291 to A295 to be important for the selection of the cleavage site on the tRNA(SerSu1) precursor. We discuss the possibility that the conformation of M1 RNA in the enzyme-substrate complex is dependent on the identity of the substrate.
J Mol Biol 1993 Jun 05
PMID:Identification of a region within M1 RNA of Escherichia coli RNase P important for the location of the cleavage site on a wild-type tRNA precursor. 768 24

In the phage-plasmid P4, both lysogenic and lytic functions are coded by the same operon. Early after infection the whole operon is transcribed from the constitutive promoter PLE. In the lysogenic condition transcription from PLE terminates prematurely and only the immunity functions, which are proximal to the promoter, are thus expressed. Fragments of the P4 immunity region were cloned in an expression vector. A DNA fragment as short as 91 bp was sufficient, when transcribed, to express P4 immunity and to complement P4 immunity deficient mutants. This fragment, like prophage P4, produced a 69 nt long RNA (CI RNA). A shorter P4 fragment neither expressed immunity nor synthesized the CI RNA. Thus the CI RNA is the P4 trans-acting immunity factor. The 5' end of the CI RNA, mapped by primer extension, does not correspond to the transcription initiation point, thus suggesting that the CI RNA is produced by processing of the primary transcript. In an RNase P mutant host the processing of the 5' end and the production of a functional CI RNA were impaired. The requirement of RNase P for the correct processing of CI appears to be related to the predicted secondary structure of the precursor CI RNA. A region (seqB) within the CI RNA shows complementarity with two cis-acting sequences (seqA and seqC) required for P4 immunity, suggesting that transcription termination may be caused by pairing of the CI RNA with the complementary target sequences on the nascent transcript.
J Mol Biol 1995 Jun 23
PMID:Immunity determinant of phage-plasmid P4 is a short processed RNA. 779 Dec 13

We show that the Th/To ribonucleoprotein is defined by (i) the co-immunoprecipitation of two RNAs, (ii) the co-immunoprecipitation of four major polypeptides and (iii) the quantitative immune recognition of both RNase P and RNase MRP. No serum was found that recognizes either one of these two enzymes exclusively. The specific co-immunoprecipitation of RNase MRP and RNase P by all Th/To ribonucleoprotein autoantibodies indicates that the anti-Th/To autoimmune response is directed against both enzymes in a quantitatively indistinguishable manner. Thus the Th/To ribonucleoprotein is defined by RNase P and RNase MRP.
Mol Biol Rep 1993 Jun
PMID:Definition of the Th/To ribonucleoprotein by RNase P and RNase MRP. 823 91

RNase P is responsible for the maturation of the 5'-termini of tRNA molecules in all cells studied to date. This ribonucleoprotein has to recognize and identify its cleavage site on a large number of different precursors. This review covers what is currently known about the function of the catalytic subunit of Escherichia coli RNase P, M1 RNA, and the protein subunit, C5, in particular with respect to cleavage-site selection. Recent genetic and biochemical data show that the two C residues in the 3'-terminal CCA sequence of a precursor interact with the enzyme through Watson-Crick base-pairing. This is suggested to result in unfolding of the amino acid acceptor-stem and exposure of the cleavage site. Furthermore, other close contact points between M1 RNA and its substrate have recently been identified. These data, together with the two existing three-dimensional structure models of M1 RNA in complex with its substrate, establish a platform that will enable us to seek an understanding of the underlying mechanism of cleavage by this elusive enzyme.
Mol Microbiol 1995 Aug
PMID:RNase P--a 'Scarlet Pimpernel'. 751 85

RNase P is a ribonucleoprotein enzyme in all organisms and organelles investigated so far, with the exception of chloroplasts where no enzyme-associated RNA has been detected to date. As an approach to answer the question whether an RNA component is present in RNase P from photosynthetic organelles, we have used a phylogenetically oriented strategy and searched for RNase P RNA in a postulated intermediate in plastid evolution, the cyanelle of Cyanophora paradoxa. We have detected a 351 nucleotide long RNA similar to cyanobacterial RNase P RNAs, with a proposed secondary structure that closely resembles a bacterial consensus. The RNA is encoded on the cyanelle genome and copurifies with enzyme activity. The RNA is not catalytically active by itself, but the activity of the cyanelle RNase P holoenzyme is destroyed by nuclease treatment, indicating an essential role of the RNA. Hence cyanelle RNase P, combining properties of bacterial and eukaryotic enzymes, occupies an intermediate position in RNA enzyme evolution. The first description of an RNA component in RNase P from a photosynthetic organelle might thus be an important step towards an understanding of plastid RNase P structure and function.
J Mol Biol 1996 Mar 22
PMID:RNase P from a photosynthetic organelle contains an RNA homologous to the cyanobacterial counterpart. 863 58

The accessibility of the ribose groups in the phosphodiester chain of M1 RNA, the catalytic subunit of ribonuclease P from Escherichia coli, has been probed with an Fe(II)-EDTA reagent when the RNA is alone in solution, when it is in a complex with a tRNA precursor substrate, and when it is in the holoenzyme complex with its cofactor, C5 protein. The regions found to be protected under these various conditions, as well as those previously identified in other chemical probing experiments, have been mapped on a three-dimensional working model of M1 RNA and are generally compatible with the previously proposed placement of the substrate on the enzyme and with previous data and inferences regarding the interactions of C5 protein with M1 RNA. On the basis of the accessibilities of the C(4') atoms, refinements have been introduced in the model to accommodate the Fe(II)-EDTA protection data. The protein cofactor makes contact with several helical regions of the catalytic RNA on the opposite side of the surface to which substrates bind.
J Mol Biol 1996 May 17
PMID:Mapping in three dimensions of regions in a catalytic RNA protected from attack by an Fe(II)-EDTA reagent. 863 95

We report a detailed evolutionary study of the RNase P- and RNase MRP- associated RNAs. The analyses were performed on all the available complete sequences of RNase MRP (vertebrates, yeast, plant), nuclear RNase P (vertebrates, yeast), and mitochondrial RNase P (yeast) RNAs. For the first time the phylogenetic distance between these sequences and the nucleotide substitution rates have been quantitatively measured.The analyses were performed by considering the optimal multiple alignments obtained mostly by maximizing similarity between primary sequences. RNase P RNA and MRP RNA display evolutionary dynamics following the molecular clock. Both have similar rates and evolve about one order of magnitude faster than the corresponding small rRNA sequences which have been, so far, the most common gene markers used for phylogeny. However, small rRNAs evolve too slowly to solve close phylogenetic relationships such as those between mammals. The quicker rate of RNase P and MRP RNA allowed us to assess phylogenetic relationships between mammals and other vertebrate species and yeast strains. The phylogenetic data obtained with yeasts perfectly agree with those obtained by functional assays, thus demonstrating the potential offered by this approach for laboratory experiments.
J Mol Evol 1996 Jul
PMID:The evolution of the RNase P- and RNase MRP-associated RNAs: phylogenetic analysis and nucleotide substitution rate. 866 Apr 29

Rpm2p is a protein subunit of Saccharomyces cerevisiae yeast mitochondrial RNase P, an enzyme which removes 5' leader sequences from mitochondrial tRNA precursors. Precursor tRNAs accumulate in strains carrying a disrupted allele of RPM2. The resulting defect in mitochondrial protein synthesis causes petite mutants to form. We report here that alteration in the biogenesis of Rpm1r, the RNase P RNA subunit, is another consequence of disrupting RPM2. High-molecular-weight transcripts accumulate, and no mature Rpm1r is produced. Transcript mapping reveals that the smallest RNA accumulated is extended on both the 5' and 3' ends relative to mature Rpm1r. This intermediate and other longer transcripts which accumulate are also found as low-abundance RNAs in wild-type cells, allowing identification of processing events necessary for conversion of the primary transcript to final products. Our data demonstrate directly that Rpm1r is transcribed with its substrates, tRNA met f and tRNAPro, from a promoter located upstream of the tRNA met f gene and suggest that a portion also originates from a second promoter, located between the tRNA met f gene and RPM1. We tested the possibility that precursors accumulate because the RNase P deficiency prevents the removal of the downstream tRNAPro. Large RPM1 transcripts still accumulate in strains missing this tRNA. Thus, an inability to process cotranscribed tRNAs does not explain the precursor accumulation phenotype. Furthermore, strains with mutant RPM1 genes also accumulate precursor Rpm1r, suggesting that mutations in either gene can lead to similar biogenesis defects. Several models to explain precursor accumulation are presented.
Mol Cell Biol 1996 Jul
PMID:Yeast mitochondrial RNase P RNA synthesis is altered in an RNase P protein subunit mutant: insights into the biogenesis of a mitochondrial RNA-processing enzyme. 866 58


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>