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. Author manuscript; available in PMC: 2015 Apr 26.
Published in final edited form as: Cell Rep. 2015 Mar 26;11(1):61–70. doi: 10.1016/j.celrep.2015.03.003

Fig. 4.

Fig. 4

Intracellular folic acid concentration. Folic acid concentration in E. coli BL21(DE3)ΔabgTΔpabA double knockout cells expressing MtrF were markedly reduced in comparison with cells transformed with the empty vector. When transformed with plasmid expressing the mutant transporter, D193A, S417A, W420A, P438A, D449A, and P457A, folic acid production was significantly increased in these cells. However, the level of intracellular folic acid concentration in BL21(DE3)ΔabgTΔpabA cells expressing R446A was nearly identical to that of the double knockout strain carrying wild-type MtrF. Each bar represents the mean of three separate cultures. “*” indicates values of BL21(DE3)ΔabgTΔpabA/pET15b and BL21(DE3)ΔabgTΔpabA cells expressing the mutant transporters that are significantly higher than that of BL21(DE3)ΔabgTΔpabA/pET15bΩmtrF expressing wild-type MtrF (P < 0.04).