FIG. 4.
Cysteine and cystine uptake by L. pneumophila strains. A. Uptake of l-[14C]cysteine by the wild type (•) and the CYS-1 mutant (▪). B. Hofstee plot of [14C]cysteine uptake by wild-type L. pneumophila. The standard deviation determined for each time point is based on three independent determinations. The dashed line indicates the high-affinity transporter and the solid line the low-affinity transporter. V/S was calculated from the initial velocities and is in picomoles/minute/milligram (dry weight)/μM cysteine, and the substrate concentration is in nanomoles per milliliter.