Fig 5.

(A) Elution profile of extracellular amino acid at the stationary phase. Wild-type and ΔyggS mutant strains were grown in M9-glucose medium at 30°C. The stationary-phase culture supernatants were collected, deproteinized, and subjected to amino acid analysis. The HPLC chromatograms generated by the amino acid analysis are shown (wild-type, solid line; ΔyggS mutant, broken line). The inset graph shows an expansion of the retention time from 25 to 40 min. The extracellular l-Val (V) concentration was 0.7 and 110 μM in the WT and ΔyggS mutant culture supernatant, respectively. The ΔyggS mutant produced 2-aminobutyrate (*), and only the WT accumulated extracellular Nle (#). (B) Intracellular amino acid composition of stationary-phase cells. Both WT (closed bar) and ΔyggS (open bar) strains were grown in M9-glucose medium at 30°C. After 24 h of cultivation, the concentrations of intracellular amino acids were determined as described in Materials and Methods.