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Active recruitment of σ 54 ‐RNA polymerase to the Pu promoter of Pseudomonas putida : role of IHF and αCTD
Author(s) -
Bertoni Giovanni,
Fujita Nobuyuki,
Ishihama Akira,
de Lorenzo Víctor
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.17.5120
Subject(s) - biology , pseudomonas putida , sigma factor , rna polymerase , polymerase , microbiology and biotechnology , genetics , rna , dna , gene
The sequence elements determining the binding of the σ 54 ‐containing RNA polymerase (σ 54 ‐RNAP) to the Pu promoter of Pseudomonas putida have been examined. Contrary to previous results in related systems, we show that the integration host factor (IHF) binding stimulates the recruitment of the enzyme to the −12/−24 sequence motifs. Such a recruitment, which is fully independent of the activator of the system, XylR, requires the interaction of the C‐terminal domain of the α subunit of RNAP with specific DNA sequences upstream of the IHF site which are reminiscent of the UP elements in σ 70 promoters. Our data show that this interaction is mainly brought about by the distinct geometry of the promoter region caused by IHF binding and the ensuing DNA bending. These results support the view that binding of σ 54 ‐RNAP to a promoter is a step that can be subjected to regulation by factors (e.g. IHF) other than the sole intrinsic affinity of σ 54 ‐RNAP for the −12/−24 site.