FIG 3.

Substituting Glu10 with Gly extends Tfa_Mu binding specificity. (A) E. coli C cells were mixed for 1 h with 100 μl of 5 μM Tfa _P2, Tfa_Mu, or the indicated Tfa_Mu mutants. The cells were then mixed with a lysate of phage P2 and plated. The number of resulting plaques was normalized to that obtained on cells that were not premixed with protein. (B) This experiment was performed in the same manner as Fig. 3A, except E. coli C cells were mixed for 1 h with increasing levels of Tfa_MuE10G. Data from Fig. 2B obtained for Tfa_Mu and Tfa _P2 are shown for comparison. (C) This experiment was performed in the same manner as Fig. 3B except that E. coli K-12 was used as the host strain. Data from Fig. 2B obtained for Tfa_Mu and Tfa _P2 are shown for comparison. The values shown are the mean of three replicates with error bars representing the standard deviation. The actual reduction in PFU under conditions of maximal inhibition by Tfa proteins was approximately 300-fold.