A novel nickel responsive MerR-like regulator, NimR, from Haemophilus influenzae
| Autor: | Karrera Y. Djoko, M. Pilar Argente, JiaQi Ng, Stephen P. Kidd, Michael P. Jennings, Alastair G. McEwan |
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| Rok vydání: | 2011 |
| Předmět: |
Urease
Operon Mutant Molecular Sequence Data Biophysics medicine.disease_cause Biochemistry Haemophilus influenzae Microbiology Biomaterials Bacterial Proteins Nickel medicine Promoter Regions Genetic Escherichia coli biology Base Sequence Membrane transport protein Metals and Alloys Wild type Membrane Transport Proteins Promoter Gene Expression Regulation Bacterial Chemistry (miscellaneous) Mutation biology.protein Transcription Factors |
| Zdroj: | Metallomics : integrated biometal science. 3(10) |
| ISSN: | 1756-591X |
| Popis: | 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 Ni(2+) 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 Ni(2+). 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 Ni(2+). 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 Ni(2+)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. |
| Databáze: | OpenAIRE |
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