Format

Send to

Choose Destination
Structure. 2011 Jul 13;19(7):999-1010. doi: 10.1016/j.str.2011.03.022.

Structure of a yeast RNase III dsRBD complex with a noncanonical RNA substrate provides new insights into binding specificity of dsRBDs.

Author information

1
Department of Chemistry and Biochemistry, P.O. Box 951569, University of California, Los Angeles, CA 90095-1569, USA.

Abstract

dsRBDs 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 α1. Our findings provide a unified model of binding site selection by this dsRBD.

PMID:
21742266
PMCID:
PMC3143303
DOI:
10.1016/j.str.2011.03.022
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center