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)

DNA-directed RNA polymerase is responsible for gene expression. Despite its importance, many details of its function and higher-order structure still remain unknown. We report here a local sequence similarity between the second largest subunit of RNA polymerase II and bacterial RNases Ba (barnase), Bi, and St. The most remarkable similarity is that the catalytic sites of the RNases are shared with the eukaryotic RNA polymerase II subunits of Drosophila melanogaster and Saccharomyces cerevisiae. Several amino acids conserved among the RNases and the RNase-like domains of the RNA polymerase subunits are located in the neighborhood of the catalytic sites of barnase, whose three-dimensional structure has been resolved. This observation suggests the functional importance of the RNase-like domain of the RNA polymerase subunits and indicates that the RNase-like domain may have RNase activity. The location of the RNase-like domain relative to the region necessary for RNA polymerization is similar to the relative proximity of 5'----3' or 3'----5' exonuclease and the region of polymerase activity of DNA polymerase I. The RNase-like domain might work in proofreading, as in RNA-directed RNA polymerase of influenza virus, or it may contribute to RNA binding through an unknown function.
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PMID:RNase-like domain in DNA-directed RNA polymerase II. 192 68

The toxicity and low success of current treatments for Leishmaniosis determines the search of new peptide drugs and/or molecular targets in Leishmania pathogen species (L. infantum and L. major). For example, Ribonucleases (RNases) are enzymes relevant to several biologic processes; then, theoretical and experimental study of the molecular diversity of Peptide Mass Fingerprints (PMFs) of RNases is useful for drug design. This study introduces a methodology that combines QSAR models, 2D-Electrophoresis (2D-E), MALDI-TOF Mass Spectroscopy (MS), BLAST alignment, and Molecular Dynamics (MD) to explore PMFs of RNases. We illustrate this approach by investigating for the first time the PMFs of a new protein of L. infantum. Here we report and compare new versus old predictive models for RNases based on Topological Indices (TIs) of Markov Pseudo-Folding Lattices. These group of indices called Pseudo-folding Lattice 2D-TIs include: Spectral moments pi ( k )(x,y), Mean Electrostatic potentials xi ( k )(x,y), and Entropy measures theta ( k )(x,y). The accuracy of the models (training/cross-validation) was as follows: xi ( k )(x,y)-model (96.0%/91.7%)>pi ( k )(x,y)-model (84.7/83.3) > theta ( k )(x,y)-model (66.0/66.7). We also carried out a 2D-E analysis of biological samples of L. infantum promastigotes focusing on a 2D-E gel spot of one unknown protein with M<20, 100 and pI <7. MASCOT search identified 20 proteins with Mowse score >30, but not one >52 (threshold value), the higher value of 42 was for a probable DNA-directed RNA polymerase. However, we determined experimentally the sequence of more than 140 peptides. We used QSAR models to predict RNase scores for these peptides and BLAST alignment to confirm some results. We also calculated 3D-folding TIs based on MD experiments and compared 2D versus 3D-TIs on molecular phylogenetic analysis of the molecular diversity of these peptides. This combined strategy may be of interest in drug development or target identification.
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PMID:QSAR for RNases and theoretic-experimental study of molecular diversity on peptide mass fingerprints of a new Leishmania infantum protein. 1957 42