Structural highlights
FunctionRNT1_YEAST DsRNA-specific nuclease that cleaves eukaryotic pre-ribosomal RNA at the U3 snoRNP-dependent A0 site in the 5'-external transcribed spacer (ETS) and in the 3'-ETS. In vitro, cleaves synthetic 5'-ETS RNA A0 site in the absence of snoRNA or other factors. Has an essential growth function in addition to pre-rRNA processing. Publication Abstract from PubMeddsRBDs often bind dsRNAs with some specificity, yet the basis for this is poorly understood. Rnt1p, the major RNase III in Saccharomyces cerevisiae, cleaves RNA substrates containing hairpins capped by A/uGNN tetraloops, using its dsRBD to recognize a conserved tetraloop fold. However, the identification of a Rnt1p substrate with an AAGU tetraloop raised the question of whether Rnt1p binds to this noncanonical substrate differently than to A/uGNN tetraloops. The solution structure of Rnt1p dsRBD bound to an AAGU-capped hairpin reveals that the tetraloop undergoes a structural rearrangement upon binding to Rnt1p dsRBD to adopt a backbone conformation that is essentially the same as the AGAA tetraloop, and indicates that a conserved recognition mode is used for all Rnt1p substrates. Comparison of free and RNA-bound Rnt1p dsRBD reveals that tetraloop-specific binding requires a conformational change in helix alpha1. Our findings provide a unified model of binding site selection by this dsRBD. Structure of a yeast RNase III dsRBD complex with a noncanonical RNA substrate provides new insights into binding specificity of dsRBDs.,Wang Z, Hartman E, Roy K, Chanfreau G, Feigon J Structure. 2011 Jul 13;19(7):999-1010. PMID:21742266[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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