Patricia Kiley

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IscR (iron-sulfur cluster regulator) is encoded by an ORF located immediately upstream of genes coding for the Escherichia coli Fe-S cluster assembly proteins, IscS, IscU, and IscA. IscR shares amino acid similarity with MarA, a member of the MarA/SoxS/Rob family of transcription factors. In this study, we found that IscR functions as a repressor of the(More)
The major regulator controlling the physiological switch between aerobic and anaerobic growth conditions in Escherichia coli is the DNA binding protein FNR. To identify genes controlled by FNR, we used Affymetrix Antisense GeneChips to compare global gene expression profiles from isogenic MG1655 wild-type and Deltafnr strains grown in glucose minimal media(More)
The transcription factor FNR from Escherichia coli regulates transcription of genes in response to oxygen deprivation. To determine how the activity of FNR is regulated by oxygen, a form of FNR had to be isolated that had properties similar to those observed in vivo. This was accomplished by purification of an FNR fraction which exhibited enhanced DNA(More)
The expression of several Escherichia coli operons is activated by the Fnr protein during anaerobic growth and is further controlled in response to nitrate and nitrite by the homologous response regulators, NarL and NarP. Among these operons, the napF operon, encoding a periplasmic nitrate reductase, has unique features with respect to its Fnr-, NarL-, and(More)
The cysteine desulfurase, IscS, provides sulfur for Fe-S cluster synthesis in vitro, but a role for IscS in in vivo Fe-S cluster formation has yet to be established. To study the in vivo function of IscS in Escherichia coli, a strain lacking IscS was constructed and characterized. Using this iscS deletion strain, we have observed decreased specific(More)
Fe-S clusters are key to the sensing and transcription functions of three transcription factors, FNR, IscR and SoxR. All three proteins were discovered in Escherichia coli but experimental data and bioinformatic predictions suggest that homologs of these proteins exist in other bacterial species, highlighting the widespread nature of Fe-S-dependent(More)
FNR is a global regulator that controls transcription of genes whose functions facilitate adaptation to growth under O2 limiting conditions. It has long been appreciated that the activity of FNR must be regulated by O2 availability, since FNR dependent gene expression is observed in vivo only under anaerobic conditions, while similar levels of this protein(More)
IscR is an iron-sulphur (Fe-S) cluster-containing transcription factor that represses transcription of the operon containing its own gene and the iscSUA-hscBA-fdx genes, whose products are involved in Fe-S cluster biogenesis. In this study, global transcriptional profiling of Escherichia coli IscR(+) and IscR(-) strains grown under aerobic and anaerobic(More)
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,(More)
Fe-S clusters are essential across the biological world, yet how cells regulate expression of Fe-S cluster biogenesis pathways to cope with changes in Fe-S cluster demand is not well understood. Here, we describe the mechanism by which IscR, a [2Fe-2S] cluster-containing regulator of Escherichia coli, adjusts the synthesis of the Isc Fe-S biogenesis pathway(More)