Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Synthesis of the oligonucleotides that prime replication of phiX174 single-stranded DNA employs complex protein machinery of the host cell which is probably used by the cell to replicate its own chromosome. Primer synthesis depends on at least five proteins (DNA binding protein, dnaB and dnaC proteins, protein i, and protein n) and ATP to form a replication intermediate and another protein, primase (dnaG protein), to assemble the oligonucleotide by template transcription. The data in this paper show that ribo- and deoxyribonucleoside triphosphates can serve as substrates and form hybrid primers when present together. Both RNA and DNA primers were initiated with ATP. At least three of the four base-pairing nucleoside triphosphates were required for the transcription that generates effective primers. Over 90% of the RNA and DNA transcripts were extended into complementary strands by DNA polymerase III holoenzyme. At optimal triphosphate concentrations, the rate and extent of primer formation were greater from ribonucleoside triphosphates than from deoxyribonucleoside triphosphates. Uncoupled from DNA replication, the length of RNA primers was 14 to 50 residues, the DNA primers 4 to 20 residues. The fingerprint pattern of an RNase digest of RNA primers has a complexity suggestive of transcription from many sites on the phiX174 template. The multienzyme priming system is highly specific for phiX174 DNA as template.
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PMID:A multienzyme system for priming the replication of phiX174 viral DNA. 34 90

A topological comparison of the two helix destabilizing proteins, pancreatic ribonuclease A and the gene 5 DNA binding protein of bacteriophage fd has been completed utilizing the available high resolution tertiary structures of each protein. The results indicate these two proteins are structurally if not also evolutionarily related. Regions of closet topological equivalence occur between beta loops directly involved in nucleotide binding or are required for the maintenance of their respective oligonucleotide binding channels. In addition, there is a similar placement of critical amino acid side chains about the binding site. Further evidence for this structural relationship is obtained by comparison of structural data for the mode of complexation of polynucleotides to each protein. The results of topological comparison suggest the essential property shared by helix destabilizing proteins, whether specialized DNA binding proteins such as G5BP or proteins with other primary functional roles, like ribonuclease A, is the presence of an elongated oligonucleotide binding channel. Although ribonuclease A and G5BP are structurally related, it seems likely any protein with this structural feature will exhibit a helix destabilizing capacity. This conclusion is supported by the diversity of molecular characteristics shown by other proteins having this activity.
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PMID:Topological comparison of two helix destabilizing proteins: ribonuclease A and the gene 5 DNA binding protein. 285 69

Bovine pancreatic ribonuclease (RNase) A and S protein (enzymatically inactive proteolytic fragment of RNase A which contains RNA binding site) stimulate the activation, as evidenced by increasing DNA-cellulose binding, of highly purified rat hepatic glucocorticoid-receptor complexes. These effects are dose dependent with maximal stimulation of DNA-cellulose binding being detected at approximately 500 micrograms (50 units of RNase A/mL). RNase A and S protein do not enhance DNA-cellulose binding via their ability to interact directly with DNA or to increase nonspecific binding of receptors to cellulose. Neither S peptide (enzymatically inactive proteolytic fragment which lacks RNA binding site) nor cytochrome c, a nonspecific basic DNA binding protein, mimics these effects. RNase A and S protein do not stimulate the conformational change which is associated with activation and is reflected in a shift in the elution profile of receptor complexes from DEAE-cellulose. In contrast, these two proteins interact with previously heat-activated receptor complexes to further enhance their DNA-cellulose binding capacity and thus mimic the effects of an endogenous heat-stable cytoplasmic protein(s) which also function(s) during step 2 of in vitro activation [Schmidt, T. J., Miller-Diener, A., Webb, M. L., & Litwack, G. (1985) J. Biol. Chem. 260, 16255-16262]. Preadsorption of RNase A and S protein to an RNase affinity resin containing an inhibitory RNA analogue, or trypsin digestion of the RNA binding site within S protein, eliminates the subsequent ability of these two proteins to stimulate DNA-cellulose binding of the purified receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of bovine pancreatic ribonuclease A, S protein, and S peptide on activation of purified rat hepatic glucocorticoid-receptor complexes. 379 Apr 97

Heterogeneous nuclear protein complexes (hnRNP) containing the precursor RNA from the adenovirus early region 2 were analysed to determine the specificity of protein-RNA interaction. RNA precursor sequences were present in isolated hnRNP complexes and endogenous 30S particles. At least 20-40 bases long fragments were protected when RNase A was used to remove unprotected RNA sequences in hnRNA complexes. Similarly around 40 bases of RNA were protected in 30S particles. These sequences represent discrete regions of the adenovirus genome. Especially sequences complementary to the EcoRI-F fragment encoding the first leader and the major intron for the DNA binding protein (DBP) RNA precursor, were analysed in detail. Tentatively, sequences resistant to RNase A were located in the middle of the intron and at the splice-donor junction of the first leader of the DBP precursor RNA. The same sequences were identified irrespective whether hnRNP complexes or 30S particles were used suggesting that 30S particles originate from hnRNP complexes. A 38.000 dalton protein appears to be in direct contact with RNA sequences complementary to the EcoRI-F fragment.
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PMID:Non-random localization of ribonucleoprotein (RNP) structures within an adenovirus mRNA precursor. 628 86

The overall derivative spectrum of a protein is the sum of the individual derivative spectra just as the overall ultraviolet spectrum of a protein is the sum of its component parts. The RNase and DNA binding protein Sso7d has two tyrosines and one tryptophan. We used two mutant forms of the protein to show that the individual aromatics contribute derivative spectra that can be explained on the basis of their environments. We used mutant forms of iso-1-cytochrome c to estimate the contributions of the single tryptophan and three of the five tyrosines to the overall derivative spectrum. The tryptophan spectrum is not exceptional. The comparable tyrosine spectra are more complex. The derivative spectrum of individual tyrosines does not correspond to that expected on the basis of concentration. This is a reflection of two factors: (1) the extent to which mutations are sensed distally through the introduction and compression of packing defects; and (2) the extent to which electronic transitions of tyrosine are influenced by nearby atoms. This influence could take the form of tyrosine residing in an area where the dielectric coefficient is not uniform; it could also result from tyrosine bumping into neighboring atoms with lower frequency than it does in solution.
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PMID:The individual tyrosines of proteins: their spectra may or may not differ from those in water or other solvents. 1020 96

A strain of Bacillus subtilis lacking two 3'-to-5' exoribonucleases, polynucleotide phosphorylase (PNPase) and RNase R, was used to purify another 3'-to-5' exoribonuclease, which is encoded by the yhaM gene. YhaM was active in the presence of Mn(2+) (or Co(2+)), was inactive in the presence of Mg(2+), and could also degrade single-stranded DNA. The half-life of bulk mRNA in a mutant lacking PNPase, RNase R, and YhaM was not significantly different from that of the wild type, suggesting the existence of additional activities that can participate in mRNA turnover. Sequence homologues of YhaM were found only in gram-positive organisms. The Staphylococcus aureus homologue, CBF1, which had been characterized as a double-stranded DNA binding protein involved in plasmid replication, was also shown to be an Mn(2+)-dependent exoribonuclease. YhaM protein has a C-terminal "HD domain," found in metal-dependent phosphohydrolases. By structure modeling, it was shown that YhaM also contains an N-terminal "OB-fold," present in many oligosaccharide- and oligonucleotide-binding proteins. The combination of these two domains is unique. Thus, YhaM and 10 related proteins from gram-positive organisms constitute a new exonuclease family.
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PMID:Bacillus subtilis YhaM, a member of a new family of 3'-to-5' exonucleases in gram-positive bacteria. 1239 95