• SURFE²R N1

    Easy-to-learn all-in-one device, ideal for teaching and university research
  • SURFE²R N1

    Finally label-free functional assays for transporters available
  • SURFE²R N1

    High signal amplification compared to patch-clamp: transport & binding assays
  • SURFE²R N1

    The only instrument on the market for SSM-based electrophysiology
  • SURFE²R N1

    Turn-key system for efficient transporter protein analysis

2012 - The nitrite transport protein NirC from Salmonella typhimurium is a nitrite/proton antiporter

Icon N1   SURFE²R-technology (custom-built system) publication in Biochimica et Biophysica Acta (BBA) - Biomembranes (2012)

Authors:
Rycovska A., Hatahet L., Fendler K., Michel H.

Journal:
Biochimica et Biophysica Acta (BBA) - Biomembranes (2012) 1818(5):1342-1350


Abstract:

In anaerobically grown bacteria, transport of nitrite is catalyzed by an integral membrane protein of the form ate–nitrite transporter family, NirC, which in Salmonella typhimurium plays a critical role in intracellular virulence. We present a functional characterization of the S. typhimurium nitrite transporter StmNirC in native membrane vesicles as well as purified and reconstituted into proteoliposomes. Using an electrophysiological technique based on solid supported membranes, we show nitrite induced translocation of negative charges into proteoliposomes reconstituted with purified StmNirC. These data demonstrate the electrogenicity of StmNirC and its substrate specificity for nitrite. Monitoring changes in ΔpH on everted membrane vesicles containing overexpressed StmNirC using acridine orange as a pH indicator we demonstrate that StmNirC acts as a secondary active transporter. It promotes low affinity transport of nitrite coupled to H+ antiport with a pH independent profile in the pH range from 6 to 8. In addition to nitrite also nitrate is transported by StmNirC, but with reduced flux and complete absence of proton antiport activity. Taken together, these data suggest a bispecific anion selectivity of StmNirC with an ion specific transport mode. This may play a role in regulating nitrite transport under physiological conditions.


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