Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angiogenin belongs to the Ribonuclease superfamily and has a weak enzymatic activity that is crucial for its biological function of stimulating blood vessel growth. Structural studies on ligand bound Angiogenin will go a long way in understanding the mechanism of the protein as well as help in designing drugs against it. In this study we present the first available structure of nucleotide ligand bound Angiogenin obtained by computer modeling. The importance of this study in itself notwithstanding, is a precursor to modeling a full dinucleotide substrate onto Angiogenin. Bovine Angiogenin, the structure of which has been solved at a high resolution, was earlier subjected to Molecular Dynamics simulations for a nanosecond. The MD structures offer better starting points for docking as they offer lesser obstruction than the crystal structure to ligand binding. The MD structure with the least serious short contacts was modeled to obtain a steric free Angiogenin - 3' mononucleotide complex structure. The structures were energetically minimized and subjected to a brief spell of Molecular Dynamics. The results of the simulation show that all the ligand-Angiogenin interactions and hydrogen bonds are retained, redeeming the structure and docking procedure. Further, following ligand - protein interactions in the case of the ligands 3'-CMP and 3'-UMP we were able to speculate on how Angiogenin, a predominantly prymidine specific ribonuclease prefers Cytosine to Uracil in the first base position.
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PMID:Modeling of angiogenin - 3-NMP complex. 1005 27

Excised root segments of Pisum sativum (L.) cut from the region 2-4 mm behind the root tip were cultured in a 2% sucrose medium containing analogues of uracil and proline. Of several uracil analogues tested only those containing a thiol group (2-thiouracil and 2-thio-6-azauracil) markedly stimulated the growth rate and prolonged the duration of growth of the segments, whereas other uracil analogues which enhanced growth affected only its duration. Uracil had no effect on cell elongation and did not completely prevent the effects of 2-thiouracil and 2-thio-6-azauracil; it did, however, prevent the stimulation by those analogues without a thiol group. Two analogues of proline, thioproline and hydroxyproline, also enhanced cell elongation but whereas the effect of hydroxyproline was completely prevented by proline, the stimulation produced by thioproline was not.During cell elongation, [(14)C]thiouracil was incorporated into RNA, where it replaced uracil, and into a non-nucleotide fraction of the cell wall from which it could not be removed with perchloric acid, sodium hydroxide, ribonuclease or pronase. Experiments using labelled thiouracil, orotic acid, leucine, proline and hydroxyproline strongly suggest that 2-thiouracil stimulates the growth rate of segments by becoming attached to cysteine in cell-wall proteins and delaying an increase in wall rigidity caused by the formation of disulphide bridges between proteins.
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PMID:Some effects of analogues of uracil on cell elongation and wall metabolism in excised pea root segments. 2443 89

MicroRNAs (miRNAs) in blood plasma are stable under high levels of ribonuclease activity and could function in tissue-to-tissue communication, suggesting that they may have distinctive structural characteristics compared with non-circulating miRNAs. In this study, the expression of miRNAs in horse plasma and their characteristic nucleotide composition were examined and compared with non-plasma miRNAs. Highly expressed plasma miRNA species were not part of the abundant group of miRNAs in non-plasma tissues, except for the eca-let-7 family. eca-miR-486-5p, -92a, and -21 were among the most abundant plasma miRNAs, and their human orthologs also belong to the most abundant group of miRNAs in human plasma. Uracil and guanine were the most common nucleotides of both plasma and non-plasma miRNAs. Cytosine was the least common in plasma and non-plasma miRNAs, although levels were higher in plasma miRNAs. Plasma miRNAs also showed higher expression levels of miRNAs containing adenine and cytosine repeats, compared with non-plasma miRNAs. These observations indicate that miRNAs in the plasma have a unique nucleotide composition.
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PMID:Expression of microRNAs in Horse Plasma and Their Characteristic Nucleotide Composition. 2673 7