Functional role and ribosomal position of the unique N-terminal region of DHX29, a factor required for initiation on structured mammalian mRNAs.
Nucleic Acids Res
; 49(22): 12955-12969, 2021 12 16.
Article
em En
| MEDLINE
| ID: mdl-34883515
ABSTRACT
Translation initiation on structured mammalian mRNAs requires DHX29, a DExH protein that comprises a unique 534-aa-long N-terminal region (NTR) and a common catalytic DExH core. DHX29 binds to 40S subunits and possesses 40S-stimulated NTPase activity essential for its function. In the cryo-EM structure of DHX29-bound 43S preinitiation complexes, the main DHX29 density resides around the tip of helix 16 of 18S rRNA, from which it extends through a linker to the subunit interface forming an intersubunit domain next to the eIF1A binding site. Although a DExH core model can be fitted to the main density, the correlation between the remaining density and the NTR is unknown. Here, we present a model of 40S-bound DHX29, supported by directed hydroxyl radical cleavage data, showing that the intersubunit domain comprises a dsRNA-binding domain (dsRBD, aa 377-448) whereas linker corresponds to the long α-helix (aa 460-512) that follows the dsRBD. We also demonstrate that the N-terminal α-helix and the following UBA-like domain form a four-helix bundle (aa 90-166) that constitutes a previously unassigned section of the main density and resides between DHX29's C-terminal α-helix and the linker. In vitro reconstitution experiments revealed the critical and specific roles of these NTR elements for DHX29's function.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Iniciação Traducional da Cadeia Peptídica
/
Ribossomos
/
Biossíntese de Proteínas
/
RNA Mensageiro
/
RNA Helicases
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Estados Unidos