Unusual organisation, complexity and redundancy at the Escherichia coli hcp-hcr operon promoter

David L. Chismon , Douglas F Browning , Gregory K. Farrant , Stephen J.W. Busby (1)

1 School of Biosciences

Expression from the Escherichia coli hcp-hcr operon promoter is optimally induced during anaerobic conditions in the presence of nitrite. This expression depends on transcription activation by FNR, which binds to a target centred at position ‑72.5 upstream of the transcript start site. Mutational analysis was exploited to identify the corresponding -10 and -35 hexamer elements. A DNA site for NarL and NarP, located at position ‑104.5, plays only a minor role, whilst NsrR binding to a DNA target centred at position +6 plays a major role in induction of the hcp‑hcr operon promoter. Electromobility shift assays show that NsrR binds to this target. The consequences of this for the kinetics of induction of the hcp‑hcr operon are discussed.

Mots clés: Life Sciences

David L. Chismon, Douglas F Browning, Gregory K. Farrant, Stephen J.W. Busby. Unusual organisation, complexity and redundancy at the Escherichia coli hcp-hcr operon promoter. Biochemical Journal, 2010, 430 (1), pp.61-68. ⟨10.1042/BJ20100623⟩. ⟨hal-00506524⟩