Single-molecule analysis reveals the mechanism of transcription activation in M. tuberculosis.
Sci Adv
; 4(5): eaao5498, 2018 05.
Article
en En
| MEDLINE
| ID: mdl-29806016
ABSTRACT
The σ subunit of bacterial RNA polymerase (RNAP) controls recognition of the -10 and -35 promoter elements during transcription initiation. Free σ adopts a "closed," or inactive, conformation incompatible with promoter binding. The conventional two-state model of σ activation proposes that binding to core RNAP induces formation of an "open," active, σ conformation, which is optimal for promoter recognition. Using single-molecule Förster resonance energy transfer, we demonstrate that vegetative-type σ subunits exist in open and closed states even after binding to the RNAP core. As an extreme case, RNAP from Mycobacterium tuberculosis preferentially retains σ in the closed conformation, which is converted to the open conformation only upon binding by the activator protein RbpA and interaction with promoter DNA. These findings reveal that the conformational dynamics of the σ subunit in the RNAP holoenzyme is a target for regulation by transcription factors and plays a critical role in promoter recognition.
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Regulación Bacteriana de la Expresión Génica
/
Activación Transcripcional
/
Mycobacterium tuberculosis
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Sci Adv
Año:
2018
Tipo del documento:
Article