Mechanisms of opening and closing of the bacterial replicative helicase.
Elife
; 72018 12 24.
Article
en En
| MEDLINE
| ID: mdl-30582519
ABSTRACT
Assembly of bacterial ring-shaped hexameric replicative helicases on single-stranded (ss) DNA requires specialized loading factors. However, mechanisms implemented by these factors during opening and closing of the helicase, which enable and restrict access to an internal chamber, are not known. Here, we investigate these mechanisms in the Escherichia coli DnaB helicaseâ¢bacteriophage λ helicase loader (λP) complex. We show that five copies of λP bind at DnaB subunit interfaces and reconfigure the helicase into an open spiral conformation that is intermediate to previously observed closed ring and closed spiral forms; reconfiguration also produces openings large enough to admit ssDNA into the inner chamber. The helicase is also observed in a restrained inactive configuration that poises it to close on activating signal, and transition to the translocation state. Our findings provide insights into helicase opening, delivery to the origin and ssDNA entry, and closing in preparation for translocation.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Contexto en salud:
3_ND
Problema de salud:
3_neglected_diseases
/
3_zoonosis
Asunto principal:
Proteínas Virales
/
Replicación del ADN
/
AdnB Helicasas
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Elife
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos