Jump to main content
Jump to site search

Issue 10, 2011
Previous Article Next Article

A novel nickel responsive MerR-like regulator, NimR, from Haemophilus influenzae

Author affiliations

Abstract

We have identified a novel regulator from the MerR family of transcription factors in the bacterial pathogen Haemophilus influenzae (HI1623; nickel-associated merR-like Regulator – NimR). NimR regulates the expression of a Ni2+ uptake transporter (NikKLMQO). The promoters for nimR and the nik operon are divergent and overlapping and NimR binds at a site between the promoter elements for nikKLMQO. Expression of this operon requires NimR and depends on Ni2+. Growth rates of the H. influenzae nimR and nikQ mutants were reduced in chemically defined media compared to the wild type and the mutants were unable to grow in the presence of EDTA. The mutant strains were less tolerant of acidic pH and the wild type Rd KW20 could not tolerate low pH in the presence of fluoramide, a urease specific inhibitor, confirming that both nickel transport and urea hydrolysis are a central process in pH control. H. influenzae nimR and nikQ strains were deficient in urease activity, but this could be specifically restored by the addition of excess Ni2+. NimR did not directly regulate the expression of urease genes but the activity of urease requires both nimR and nikQ. Purified NimR is a dimer that binds 1 Ni2+ion. NimR is the first example of a Ni-dependent regulator from the MerR family and targeting a metal ion uptake system; it is distinct from NikR the Ni-responsive regulators of the ribbon-helix-helix family.

Graphical abstract: A novel nickel responsive MerR-like regulator, NimR, from Haemophilus influenzae

Back to tab navigation

Supplementary files

Publication details

The article was received on 05 Aug 2011, accepted on 08 Sep 2011 and first published on 23 Sep 2011


Article type: Paper
DOI: 10.1039/C1MT00127B
Citation: Metallomics, 2011,3, 1009-1018
  •   Request permissions

    A novel nickel responsive MerR-like regulator, NimR, from Haemophilus influenzae

    S. P. Kidd, K. Y. Djoko, J. Ng, M. P. Argente, M. P. Jennings and A. G. McEwan, Metallomics, 2011, 3, 1009
    DOI: 10.1039/C1MT00127B

Search articles by author

Spotlight

Advertisements