A two-subunit bacterial sigma-factor activates transcription in Bacillus subtilis.
Proc Natl Acad Sci U S A
; 106(50): 21323-8, 2009 Dec 15.
Article
em En
| MEDLINE
| ID: mdl-19940246
ABSTRACT
The sigma-like factor YvrI and coregulator YvrHa activate transcription from a small set of conserved promoters in Bacillus subtilis. We report here that these two proteins independently contribute sigma-region 2 and sigma-region 4 functions to a holoenzyme-promoter DNA complex. YvrI binds RNA polymerase (RNAP) through a region 4 interaction with the beta-subunit flap domain and mediates specific promoter recognition but cannot initiate DNA melting at the -10 promoter element. Conversely, YvrHa possesses sequence similarity to a conserved core-binding motif in sigma-region 2 and binds to the N-terminal coiled-coil element in the RNAP beta'-subunit previously implicated in interaction with region 2 of sigma-factors. YvrHa plays an essential role in stabilizing the open complex and interacts specifically with the N-terminus of YvrI. Based on these results, we propose that YvrHa is situated in the transcription complex proximal to the -10 element of the promoter, whereas YvrI is responsible for -35 region recognition. This system presents an unusual example of a two-subunit bacterial sigma-factor.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator sigma
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Bacillus subtilis
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Proteínas de Bactérias
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Ativação Transcricional
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Proteínas de Ligação a DNA
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article