Structural basis for RNA-duplex unwinding by the DEAD-box helicase DbpA.
RNA
; 29(9): 1339-1354, 2023 09.
Article
em En
| MEDLINE
| ID: mdl-37221012
DEAD-box RNA helicases are implicated in most aspects of RNA biology, where these enzymes unwind short RNA duplexes in an ATP-dependent manner. During the central step of the unwinding cycle, the two domains of the helicase core form a distinct closed conformation that destabilizes the RNA duplex, which ultimately leads to duplex melting. Despite the importance of this step for the unwinding process no high-resolution structures of this state are available. Here, I used nuclear magnetic resonance spectroscopy and X-ray crystallography to determine structures of the DEAD-box helicase DbpA in the closed conformation, complexed with substrate duplexes and single-stranded unwinding product. These structures reveal that DbpA initiates duplex unwinding by interacting with up to three base-paired nucleotides and a 5' single-stranded RNA duplex overhang. These high-resolution snapshots, together with biochemical assays, rationalize the destabilization of the RNA duplex and are integrated into a conclusive model of the unwinding process.
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MEDLINE
Assunto principal:
RNA Helicases DEAD-box
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article