Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Limited T1 RNase digestion of subfragments of the SV40 DNA restriction endonuclease fragment EcoRII-G were prepared and analyzed. The fragments were separately labeled with 32P at their 5' terminus and the terminal sequences analyzed with limited snake venom diesterase digestion. The data permitted us to deduce the nucleotide sequence for EcoRII-G. The sequence contains a stretch of 17 A-T base pairs preceding the DNA complementary to the 5' end of "early" message RNA, a stretch of 27 bases with a perfect 2-fold rotational symmetry near the origin of DNA replication and a perfect tandem repeat of 21 nucleotides.
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PMID:Nucleotide sequence of a fragment of SV40 DNA that contains the origin of DNA replication and specifies the 5' ends of "early" and "late" viral RNA. III. Construction of the total sequence of EcoRII-G fragment of SV40 DNA. 18 10

Bovine pancreatic ribonuclease is a DNA "melting" protein, since it binds with greater overall affinity to the single-stranded than to the double-stranded form of natural and synthetic deoxyribose-containing polynucleotides. As such, the DNA-RNase system provides a simple model for the more complex and biologically relevant melting protein-nucleic acid systems. Aspects of the DNA-RNase interactions which are related to the quantitative assessment of this system as a melting protein model are investigated here. A boundary sedimentation velocity technique is used to measure thermodynamic parameters of the interaction; association constants (Kh and Kc) and site sizes (nh and nc) are determined for the interaction of ribonuclease with native (double helical) and denatured (random coil) DNA. It is shown that log Kh and log Kc are linear functions of log [Na+], binding decreasing with increasing Na+ concentration, with Kh about 2 orders of magnitude smaller than Kc at the ionic strengths studied, nh and nc are approximately 8 and approximately 11 nucleotide residues, respectively, indicating that potential binding sites overlap. Binding to both forms of DNA is non-cooperative. It is shown by CD and ultraviolet spectroscopy that the binding of RNase to single- and double-stranded DNA perturbs the conformations of these polynucleotide conformations very little relative to the unliganded structures. Hydrodynamic methods are used to show that RNase binds to native DNA without altering the overall solution structure of the latter; however conditons which permit binding to, and stabilization of, transiently exposed single-stranded sequences result in a collapse of the stiff native DNA structure. We demonstrate by melting transition studies that ribonuclease does bring about an equilibrium destabilization of native DNA and poly [d(A-T)] and, by applying a ligand-perturbed helic in equilibrium coil theory developed by McGhee (McGhee, J.D. (1976) Biopolymers 15, 1345-1375), it is shown that the extent of the observed destabilization is in semiquantitative accord with expectations based on the measured affinity constants and site sizes for RNase binding to both DNA conformations. Spectral methods are used to show that the relative stability of native DNA sequences of varying base composition is the same in the presence and absence of ribonuclease, strongly arguing that this "melting" ligand "traps" single-stranded sequences transiently exposed by thermal fluctuations. RNase also undergoes an order in equilibrium disorder conformational transition as a function of temperature (the denatured form of RNase stabilizes native DNA, while native RNase destabilizes the native double helix), and the coupled equilibria involved in these interacting conformational changes are interpreted and discussed as possible models of genome regulatory interactions.
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PMID:DNA "melting" proteins. I. Effects of bovine pancreatic ribonuclease binding on the conformation and stability of DNA. 99 11

During chain elongation RNA polymerase exists as a ternary DNA-enzyme-RNA complex in which a discrete length of the nascent RNA chain proximal to the 3'-OH terminus will be bound to the product binding site (Krakow, J. S., and Fronk, E. (1969) J. Biol. Chem. 244, 5988). We have utilized the poly[d(A-T)]-directed reaction to determine the length of the nascent poly[r(A-U)] protected from attack by pancreatic ribonuclease. Following release of the ribonuclease resistant oligo[r(A-U)] from the ternary complex, its size was determined by ion exchange chromatography on DEAE-cellulose, gel filtration on Bio-Gel P-10, and the ratio of 3'-terminal uridine to internal 2':3'-UMP following alkaline hydrolysis. The results indicate that the length of the nascent protected fragment is approximately 12 residues.
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PMID:Studies on the product binding sites of the Azotobacter vinelandii ribonucleic acid polymerase. 112 30

Dinucleotides (3'-5')-ApU and UpA and their 3'-O-phosphonylmethyl and 5'-O-phosphonylmethyl analogues were studied as substrates in the primed abortive synthesis catalysed by Escherichia coli DNA-dependent RNA polymerase on poly[d(A-T)] template. All phosphonate analogues of dinucleotides containing the anomalous sugar-phosphate backbone are substrates for the holoenzyme as verified by RNase A and RNase T2 digestion of the trinucleotide analogues obtained. The finding that phosphonate dinucleotides act as primers for transcription indicates that steric requirements at the initiation site are not as specific as previously supposed. Analysis of kinetic constants of ordered bibi reaction Kia, KmA, KmB and Vmax suggests that the instability of short RNA-DNA hybrids contributes to the abortive release of trinucleotides formed.
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PMID:Phosphonate analogues of dinucleotides as substrates for DNA-dependent RNA polymerase from Escherichia coli in primed abortive initiation reaction. 248 57

An endonuclease specific for cruciform junctions has been purified from yeast cells treated with a DNA-damaging agent. The activity was followed through five chromatographic steps by assaying for the linearization of supercoiled plasmid DNA, which extrudes cruciform structures in vitro. The sites of cleavage on pColIR215 were sequenced, and nicks were located to positions symmetrically opposed across the cruciform junction. The products of cleavage were unit length linear duplexes that contained terminal hairpin loops. In contrast to pColIR215, the cleavage patterns of pXG540 plasmid DNA were found to be complex, and cuts were found up to 40 bases from an (A-T)34 sequence that extrudes into a cruciform. Little or no activity could be detected on single-stranded DNA, linear duplex DNA, or nicked circular duplex DNA. The nuclease was insensitive to RNase but was inactivated by treatment with proteinase K. Mg2+ was required as cofactor and could not be replaced by Mn2+, Ca2+, Co2+, or Cu2+. The native molecular weight of the activity was approximately 200,000 as estimated by gel filtration.
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PMID:Purification and properties of a nuclease from Saccharomyces cerevisiae that cleaves DNA at cruciform junctions. 330 13

A ribonuclease isolated earlier from bovine seminal plasma by DNA-affinity chromatography (Ramakrishnamurti, T. and Pandit, M.W. (1983) J. Chromatogr. 260, 216-222) has now been shown by thermal denaturation studies to destabilize the double-helical structure of DNA and poly[d(A-T).d(A-T)]. Thermal denaturation profiles of DNA in the presence of the protein are much more complicated due to the denaturation of protein itself in the temperature range over which DNA predominantly melts. The protein shows relatively stronger affinity towards denatured DNA as compared to native DNA. The action of micrococcal nuclease on DNA and its complexes with ribonuclease A and bovine seminal ribonuclease indicates that both of these proteins destabilize the double-helical structure of native DNA and thereby render the DNA more sensitive to the micrococcal nuclease.
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PMID:Helix-destabilization of deoxyribonucleic acid and poly[d(A-T).d(A-T)] by bovine seminal ribonuclease. 370 65