Identification of a contact site for different transcription activators in region 4 of the Escherichia coli RNA polymerase sigma70 subunit.
J Mol Biol
; 284(5): 1353-65, 1998 Dec 18.
Article
en En
| MEDLINE
| ID: mdl-9878355
The sigma subunit of RNA polymerase orchestrates basal transcription by first binding to core RNA polymerase and then recognizing promoters. Using a series of 16 alanine-substitution mutations, we show that residues in a narrow region of Escherichia coli sigma70 (590 to 603) are involved in transcription activation by a mutationally altered CRP derivative, FNR and AraC. Homology modeling of region 4 of sigma70 to the closely related NarL or 434 Cro proteins, suggests that the five basic residues implicated in activation are either in the C terminus of a long recognition helix that includes residues recognizing the -35 hexamer region of the promoter, or in the subsequent loop, and are ideally positioned to permit interaction with activators. The only substitution that has a significant effect on activator-independent transcription is at R603, indicating that this residue of sigma70 may play a distinct role in transcription initiation.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Factor sigma
/
Proteínas Bacterianas
/
ARN Polimerasas Dirigidas por ADN
/
Transactivadores
/
Proteínas de Escherichia coli
/
Escherichia coli
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
Idioma:
En
Revista:
J Mol Biol
Año:
1998
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos