Fig. 3.

The contribution of threonine transporters to serine uptake. Cells of the indicated strains were grown in C‐Glc minimal medium to an OD₆₀₀ of 1.0 and serial dilutions (10‐fold) were prepared. These samples were plated on C‐Glc minimal plates containing no serine or 1 mM serine. The plates were incubated at 37°C for 48 h.

A. Combination of the ybeC deletion with the deletion of the serA gene encoding phosphoglycerate dehydrogenase. The growth of the single deletion mutants of ybeC (GP1886) and serA (GP2392) was compared with the growth of the combined deletion strain of ybeC and serA (GP2941).

B. The resistance of the threonine transporter deletion strains to serine. The bcaP (BKE09460) and ybxG deletion strains (GP2396) are compared with the wild type strain 168 and the ybeC deletion strain (GP1886). C. Combination of the serA deletion with the deletion strain if bcaP, ybeC and ybxG. The growth of the wild type strain 168 was compared with GP2392 (serA), GP2955 (serA bcaP ybeC ybxG) and GP2950 (bcaP ybeC ybxG).