The RpoN-box motif of the RNA polymerase sigma factor σ^N plays a role in promoter recognition

Authors: Taylor, Mark; Butler, Robin; Chambers, Sheila; Casimiro, Matthew; Badii, Farah; Merrick, Mike

Source: Molecular Microbiology, Volume 22, Number 5, December 1996 , pp. 1045-1054(10)

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Abstract:

The RNA polymerase sigma factor σ^N (σ⁵⁴) is characterized by the presence, near the C-terminal end of the protein, of a highly conserved sequence of 10 amino acids (ARRTVAKYRE) that has been termed the RpoN box. In order to examine the function of this motif, which is predicted to adopt an α-helical stucture, we have isolated a number of mutations that alter residues within the box and examined the properties of the σ^N derivatives encoded by them. Certain mutations that alter charged and potentially exposed residues within the motif result in transcriptionally inactive proteins with impaired promoter recognition but no impairment in core RNA polymerase binding. We therefore suggest that the RpoN box could play a direct or indirect role in recognition of the −24, −12 promoter consensus that is characteristic of σ^N-dependent genes.

Document Type: Research article

DOI: http://dx.doi.org/10.1046/j.1365-2958.1996.01547.x

Affiliations: 1: The Nitrogen Fixation Laboratory, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.

Publication date: 1996-12-01