Major facilitator superfamily transporter NorC (NorC)

NorC is a 14-transmembrane-helix protein belonging to the major facilitator superfamily transporters, predominantly found in bacteria such as Staphylococcus aureus where it contributes to multidrug resistance by exporting various toxic compounds, including fluoroquinolone antibiotics, out of the cell. The transporter is evolutionarily related to other multidrug efflux pumps but forms a distinct clade with high sequence similarity to NorB. NorC does not efficiently transport some typical MFS substrates but binds organic cations like tetraphenylphosphonium. Structural studies have revealed drug-blocking strategies, such as the use of single-domain camelid antibodies that physically occlude the transporter’s substrate vestibule, making NorC a potential target for new resistance-breaking therapeutics.

Other names

NorC transporterMFS transporter NorC

Efflux of antibiotics and xenobiotics from bacterial cells, decreasing intracellular drug concentration and conferring resistance. Antibody-mediated blockade occurs when antibodies bind the extracellular domain, blocking access and inhibiting function.