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Solution structure of conserved AGNN tetraloops: insights into Rnt1p RNA processing.

ABSTRACT: Rnt1p, the yeast orthologue of RNase III, cleaves rRNAs, snRNAs and snoRNAs at a stem capped with conserved AGNN tetraloop. Here we show that 9 bp long stems ending with AGAA or AGUC tetraloops bind to Rnt1p and direct specific but sequence-independent RNA cleavage when provided with stems longer than 13 bp. The solution structures of these two tetraloops reveal a common fold for the terminal loop stabilized by non-canonical A-A or A-C pairs and extensive base stacking. The conserved nucleotides are stacked at the 5' side of the loop, exposing their Watson-Crick and Hoogsteen faces for recognition by Rnt1p. These results indicate that yeast RNase III recognizes the fold of a conserved single-stranded tetraloop to direct specific dsRNA cleavage.

SUBMITTER: Lebars I

PROVIDER: S-EPMC125334 | biostudies-literature | 2001 Dec

REPOSITORIES: biostudies-literature

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Solution structure of conserved AGNN tetraloops: insights into Rnt1p RNA processing.

Lebars I I Lamontagne B B Yoshizawa S S Aboul-Elela S S Fourmy D D

The EMBO journal 20011201 24

Rnt1p, the yeast orthologue of RNase III, cleaves rRNAs, snRNAs and snoRNAs at a stem capped with conserved AGNN tetraloop. Here we show that 9 bp long stems ending with AGAA or AGUC tetraloops bind to Rnt1p and direct specific but sequence-independent RNA cleavage when provided with stems longer than 13 bp. The solution structures of these two tetraloops reveal a common fold for the terminal loop stabilized by non-canonical A-A or A-C pairs and extensive base stacking. The conserved nucleotides ...[more]

PMID: 11743001

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