In vitro interaction of the IHF-like proteins Acinetobacter junii and Proteus vulgaris with ihf sites

The ability of the IHF-like proteins of Acinetobacter junii and Proteus vulgaris to interact with the H' attP and pR' ihf sites of lambda DNA was investigated. IHF from A. junii and P. vulgaris was found to bind the examined ihf sites in a way similar to IHF from Escherichia coli as shown by gel mobility shift DNA binding assays and footprinting analysis. The three IHF proteins bound to the pR' ihf site that overlaps the-35 region of that promoter and in vitro repression of transcription by each IHF was observed. These results confirm that IHF-like proteins from Gram-negative bacteria can recognize the same specific DNA sequences and appear to be important in regulation of transcription.