FIGURE 7.

Impact of the substitution of Ala-404 on PutP function. A, normalized initial rates of transport (black) and maximum accumulation of proline in E. coli WG170 (gray). Transport was analyzed as described in the legend of Fig. 2. Transport activities are normalized to the amount of PutP based on Western blot analysis. B, relative amounts of PutP with given amino acid replacements in E. coli WG170 membranes as determined by Western blot analysis. C, l-proline binding to membrane vesicles containing PutP variants detected by DRaCALA. Binding was analyzed as described in the legend of Fig. 2.