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Conservation of sigma-core RNA polymerase proximity relationships between the enhancer-independent and enhancer-dependent sigma classes.
- Source :
- EMBO Journal; 6/15/2000, Vol. 19 Issue 12, p3038-3048, 11p
- Publication Year :
- 2000
-
Abstract
- Two distinct classes of RNA polymerase sigma factors (σ) exist in bacteria and are largely unrelated in primary amino acid sequence and their modes of transcription activation. Using tethered iron chelate (Fe-BABE) derivatives of the enhancer-dependent σ<superscript>54</superscript>, we mapped several sites of proximity to the β and β′ subunits of the core RNA polymerase. Remarkably, most sites localized to those previously identified as close to the enhancer-independent σ<superscript>70</superscript> and σ<superscript>38</superscript>. This indicates a common use of sets of sequences in core for interacting with the two σ classes. Some sites chosen in σ<superscript>54</superscript> for modification with Fe-BABE were positions, which when mutated, deregulate the σ<superscript>54</superscript> holoenzyme and allow activator-independent initiation and holoenzyme isomerization. We infer that these sites in σ<superscript>54</superscript> may be involved in interactions with the core that contribute to maintenance of alternative states of the holoenzyme needed for either the stable closed promoter complex conformation or the isomerized holoenzyme conformation associated with the open promoter complex. One site of σ<superscript>54</superscript> proximity to the core is apparently not evident with σ<superscript>70</superscript>, and may represent a specialized interaction. [ABSTRACT FROM AUTHOR]
- Subjects :
- RNA polymerases
IMINO acids
PROTEINS
CATALYST supports
ISOMERIZATION
BIOCHEMISTRY
Subjects
Details
- Language :
- English
- ISSN :
- 02614189
- Volume :
- 19
- Issue :
- 12
- Database :
- Complementary Index
- Journal :
- EMBO Journal
- Publication Type :
- Academic Journal
- Accession number :
- 13004828
- Full Text :
- https://doi.org/10.1093/emboj/19.12.3038