2.A.7.3.82
Riboflavin (RF) uptake porter, ImpX, of 302 aas and 10 TMSs.  Functional complementation, growth inhibition experiments, direct uptake experiments and inhibition studies, suggesting a high degree of specificity for RF uptake (Rodionova et al. 2019). The EC50 for growth with RF was estimated to be in the range 0.5-1 µM, estimated from the half-maximal RF concentration supporting the growth of a RF auxotrophic Escherichia coli strain, but the K_half for RF uptake was 20 µM. Transport experiments suggested that the energy source is the proton motive force, but that NaCl stimulates uptake (Rodionova et al. 2019).