Structures of the Rhodopsin-Transducin Complex: Insights into G-Protein Activation.
Mol Cell
; 75(4): 781-790.e3, 2019 08 22.
Article
en En
| MEDLINE
| ID: mdl-31300275
ABSTRACT
Rhodopsin (Rho), a prototypical G-protein-coupled receptor (GPCR) in vertebrate vision, activates the G-protein transducin (GT) by catalyzing GDP-GTP exchange on its α subunit (GαT). To elucidate the determinants of GT coupling and activation, we obtained cryo-EM structures of a fully functional, light-activated Rho-GT complex in the presence and absence of a G-protein-stabilizing nanobody. The structures illustrate how GT overcomes its low basal activity by engaging activated Rho in a conformation distinct from other GPCR-G-protein complexes. Moreover, the nanobody-free structures reveal native conformations of G-protein components and capture three distinct conformers showing the GαT helical domain (αHD) contacting the Gßγ subunits. These findings uncover the molecular underpinnings of G-protein activation by visual rhodopsin and shed new light on the role played by Gßγ during receptor-catalyzed nucleotide exchange.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Rodopsina
/
Transducina
/
Complejos Multiproteicos
Límite:
Animals
Idioma:
En
Revista:
Mol Cell
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2019
Tipo del documento:
Article
País de afiliación:
Estados Unidos