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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have studied variants of Escherichia coli RNase P RNA with base exchanges in the joining regions flanking helix P18, which form part of the ribozyme core structure. Mutant RNase P RNAs were analyzed for: (1) specific tRNA binding by gel retardation; (2) catalytic performance in single turnover reactions; (3) structural perturbations utilizing Pb2+ -induced hydrolysis; and (4) in vivo function by complementation analysis in E. coli RNase P mutant strains. Our in vitro experiments revealed that the base moieties of nucleotides (nt) 303 and 331 to 333 neither significantly contribute to tRNA binding or structural stabilization of RNase P RNA nor to active site chemistry. Single base exchanges at nt 300, 301, and 330 reduced tRNA binding, while having little effect on the catalytic rate, which demonstrates that these nucleotides are involved in forming the high affinity (pre-)tRNA binding site. In contrast, point mutations at the strictly conserved positions nt 328, 329, 334 and 335 reduced tRNA binding affinity as well as the catalytic rate, suggesting that these mutations additionally disrupted important interactions in the catalytic center. Probing by Pb2+ revealed that particularly the mutations that affected catalytic function most strongly perturbed a more extended region (nt 248 to 335) known to be involved in tRNA binding. Under high salt conditions (> or = 0.8 M NH4+), catalytic defects of the mutant RNase P RNAs were much less pronounced, suggesting that structural perturbations leading to increased electrostatic repulsion between phosphate groups were the main cause for observed functional defects. Only mutant C334 retained a largely increased pre-steady-state K(m(pss)) under high salt conditions. We conclude that the base at position 334 is directly involved in a contact crucial to pre-tRNA binding. A complementation analysis demonstrated the important role in vivo of the joining regions flanking helix P18. None of the bases could be mutated without affecting bacterial viability.
J Mol Biol 1996 Jun 14
PMID:Mutational analysis of the joining regions flanking helix P18 in E. coli RNase P RNA. 867 78

We have studied the expression of 4.5 S RNA and M1 RNA, the catalytic subunit of Escherchia coli RNase P, under various growth conditions. Both RNA species increase in abundance as a function of growth rate. There are roughly 450 molecules of 4.5 S RNA and 80 molecules of M1 RNA per cell at 0.4 doubling per hour, and this is increased to 5300 and 1060 molecules per cell, respectively, at 2.7 doublings per hour. Deletion of both relA and spoT, the two genes that are responsible for synthesis of ppGpp, does not affect the rate of synthesis of either RNA species. However, deletion of fis renders the expression of 4.5 S RNA independent of growth rate, but has little effect on the expression of M1 RNA. These data suggest that the expression of both 4.5 S RNA and M1 RNA genes are growth-rate regulated, but not through the same mechanism. The growth-rate dependent accumulation of 4.5 S RNA depends on FIS-mediated trans-activation, whereas that of M1 RNA is not governed by ppGpp or by FIS.
J Mol Biol 1996 Aug 23
PMID:Growth rate regulation of 4.5 S RNA and M1 RNA the catalytic subunit of Escherichia coli RNase P. 878 Jul 71

RNase MRP is a ribonucleoprotein enzyme with a structure similar to RNase P. It is required for normal processing of precursor rRNA, cleaving it in the Internal Transcribed Spacer 1.
Mol Biol Rep
PMID:RNase MRP and rRNA processing. 890 90

RNase MRP cleaves the yeast pre-rRNA at a site in internal transcribed spacer 1 (ITS1) and this cleavage can be reproduced in vitro by the highly purified enzyme. Two protein components (Pop1p and Pop2p) have been identified which are common to yeast RNase MRP and RNase P. Moreover, purified RNase P can also cleave the pre-rRNA substrate in vitro, underlining the similarities between these particles. Genetic evidence suggests that RNase MRP functionally interacts with the snoRNPs which are required for other pre-RNA processing reactions.
Mol Biol Rep
PMID:Genetic and biochemical analyses of yeast RNase MRP. 890 91

RNase P recognizes many different precursor tRNAs as well as other substrates and cleaves all of them accurately at the expected position. RNase P recognizes the tRNA structure of the precursor tRNA by a set of interactions between the catalytic RNA subunit and the T- and acceptor-stems mainly, although residues in the 5'-leader sequence as well as the 3'-terminal CCA are important. These conclusions have been reached by several studies on mutant precursor tRNAs as well as cross-linking studies between RNase P RNA and precursor tRNAs. The protein subunit of RNase P seems also to affect the way that the substrate is recognized as well as the range of substrates that can be used by RNase P, although the protein does not seem to interact directly with the substrates. The interaction between the protein and RNA subunits of RNase P has been extensively studied in vitro. The protein subunit sequence is not highly conserved among bacteria, however different proteins are functionally equivalent as heterologous reconstitution of the RNase P holoenzyme can be achieved in many cases.
Mol Biol Rep
PMID:RNase P from bacteria. Substrate recognition and function of the protein subunit. 890 95

RNase P, the enzyme response for 5'-end processing of tRNAs and 4.5S RNA, has been extensively characterized from E. coli. The RNA component of E. coli RNase P, without the protein, has the enzymatic activity and is the first true RNA enzyme to be characterized. RNase P and MRP are two distinct nuclear ribonucleoprotein (RNP) particles characterized in many eukaryotic cells including human, yeast and plant cells. There are many similarities between RNase P and MRP. These include: (1) sequence specific endonuclease activity; (2) homology at the primary and secondary structure levels; and (3) common proteins in both the RNPs. It is likely that RNase P and MRP originated from a common ancestor.
Mol Biol Rep
PMID:Structural and functional similarities between MRP and RNase P. 890 92

The ubiquitous occurrence of ribonuclease P (RNase P) as a ribonucleoprotein and the catalytic properties of bacterial RNase P RNAs indicate that RNA fulfills an ancient and important role in the function of this enzyme. This review focuses on efforts to determine the structure of the bacterial RNase P RNA ribozyme. Phylogenetic comparative analysis of a library of bacterial RNase P RNA sequences has resulted in a well-developed secondary structure model and allowed identification of some elements of tertiary structure. The native structure has been redesigned by circular permutation to facilitate intra- and inter-molecular crosslinking experiments in order to gain further structural information. The crosslinking constraints, together with the constraints provided by comparative analyses, have been incorporated into a first-order model of the structure of of the ribozyme-substrate complex. The developing structural perspective allows the design of self-cleaving pre-tRNA-RNase P RNA conjugates which are useful tools for additional structure-probing experiments.
Mol Biol Rep
PMID:Analysis of the tertiary structure of bacterial RNase P RNA. 890 97

There are at least six small stable RNAs in Mycoplasma capricolum cells besides tRNAs and rRNAs. One of them, MCS5 RNA, is a homolog of RNase P RNA. The predicted secondary structure of this RNA is essentially the same as that of other eubacterial RNase P RNAs. MCS5 RNA is more similar to the RNase P RNA of B. Subtilis than to that of E. coli. This is consistent with previous conclusions that mycoplasmas are phylogenetically related to the low G + C Gram-positive bacterial group. The major substrates for MCS5 RNA must be the precursors of tRNAs. The precursor of MCS6 RNA, which is a homolog of the E. coli 10Sa RNA, may also be a substrate for the MCS5 RNA because this RNA has a tRNA-like structure at its 5' and 3' ends.
Mol Biol Rep
PMID:RNase P RNA of Mycoplasma capricolum. 890 98

Early work on E. coli ribonuclease P led to the detailed characterization of the native enzyme, which culminated in the discovery and initial characterization of M1 RNA and the demonstration that E. coli RNase P contains an essential RNA component.
Mol Biol Rep
PMID:Early studies of native ribonuclease P, including discovery of its essential RNA component. 890 94

An important approach to understanding RNA-based catalytic function by ribonuclease P is the investigation of its evolutionary diversity in structure and function. Because RNase P enzymes from all organisms are thought to share common ancestry, the fundamental features of structure and biochemistry should be conserved in all of its modern forms. In contrast to the bacterial enzyme, the RNase P enzymes from Eucarya, organelles, and Archaea are poorly understood. This review describes our nascent understanding of the structure and function of RNase P in Archaea, and how this enzyme compares to its homologs in the other evolutionary Domains.
Mol Biol Rep
PMID:Ribonuclease P structure and function in Archaea. 890 99


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