4oun
Crystal Structure of Mini-ribonuclease 3 from Bacillus subtilis
Structural highlights
FunctionMRNC_BACSU Involved in correct processing of both the 5' and 3' ends of 23S rRNA precursor. Processes 30S rRNA precursor transcript even in absence of ribonuclease 3 (Rnc); Rnc processes 30S rRNA into smaller rRNA precursors. Cleaves more efficiently on assembled 50S ribosomal subunits. Cleavage is strongly stimulated by ribosomal protein L3 (RplC); 20-30% DMSO can replace RplC, suggesting RplC may alter rRNA conformation.[1] Publication Abstract from PubMedRibonucleases (RNases) play a critical role in RNA processing and degradation by hydrolyzing phosphodiester bonds (exo- or endonucleolytically). Many RNases that cut RNA internally exhibit substrate specificity, but their target sites are usually limited to one or a few specific nucleotides in single-stranded RNA and often in a context of a particular three-dimensional structure of the substrate. Thus far, no RNase counterparts of restriction enzymes have been identified which could cleave double-stranded RNA (dsRNA) in a sequence-specific manner. Here, we present evidence for a sequence-dependent cleavage of long dsRNA by RNase Mini-III from Bacillus subtilis (BsMiniIII). Analysis of the sites cleaved by this enzyme in limited digest of bacteriophage Phi6 dsRNA led to the identification of a consensus target sequence. We defined nucleotide residues within the preferred cleavage site that affected the efficiency of the cleavage and were essential for the discrimination of cleavable versus non-cleavable dsRNA sequences. We have also determined that the loop alpha5b-alpha6, a distinctive structural element in Mini-III RNases, is crucial for the specific cleavage, but not for dsRNA binding. Our results suggest that BsMiniIII may serve as a prototype of a sequence-specific dsRNase that could possibly be used for targeted cleavage of dsRNA. Sequence-specific cleavage of dsRNA by Mini-III RNase.,Glow D, Pianka D, Sulej AA, Kozlowski LP, Czarnecka J, Chojnowski G, Skowronek KJ, Bujnicki JM Nucleic Acids Res. 2015 Mar 11;43(5):2864-73. doi: 10.1093/nar/gkv009. Epub 2015 , Jan 29. PMID:25634891[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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