Structural and dynamic mechanisms for coupled folding and tRNA recognition of a translational T-box riboswitch.
Nat Commun
; 14(1): 7394, 2023 11 15.
Article
em En
| MEDLINE
| ID: mdl-37968328
ABSTRACT
T-box riboswitches are unique riboregulators where gene regulation is mediated through interactions between two highly structured RNAs. Despite extensive structural insights, how RNA-RNA interactions drive the folding and structural transitions of T-box to achieve functional conformations remains unclear. Here, by combining SAXS, single-molecule FRET and computational modeling, we elaborate the folding energy landscape of a translational T-box aptamer consisting of stems I, II and IIA/B, which Mg2+-induced global folding and tRNA binding are cooperatively coupled. smFRET measurements reveal that high Mg2+ stabilizes IIA/B and its stacking on II, which drives the pre-docking of I and II into a competent conformation, subsequent tRNA binding promotes docking of I and II to form a high-affinity tRNA binding groove, of which the essentiality of IIA/B and S-turn in II is substantiated with mutational analysis. We highlight a delicate balance among Mg2+, the intra- and intermolecular RNA-RNA interactions in modulating RNA folding and function.
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1
Base de dados:
MEDLINE
Assunto principal:
Riboswitch
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article