FIG. 6.

Dependence of AmyQ secretion on the content of PrsA protein in the cell. Strains IH7163(::pKTH3362, pKTH10) (A and C) and IH7162(::pKTH1601, pKTH3327) (B and D) were grown to late exponential phase in the presence of various concentrations of IPTG. The cellular level of PrsA (white bars) was determined as described in the legend to Fig. 5. Secreted α-amylase (grey bars) was determined enzymatically from the culture medium. Values represent the means of triplicate determinations. Numbers of PrsA and AmyQ molecules (C and D) per cell were calculated using the data in panels A and B, and cell densities of the cultures were determined by counting with a Petroff-Hausser counting chamber.