FIG. 8.

The competition between Mlc and glucokinase for PtsG binding affects the expression of malT. Two situations are shown. On the right-hand side, the “normal” situation is shown. A certain portion of Mlc, the repressor of malT, is bound by PtsG and is not available for the inhibition of malT transcription. On the left-hand side, the overexpression of Glk is shown. The high concentration of Glk replaces Mlc on PtsG. The increased concentration of Mlc leads to the inhibition of malT transcription and therefore to a reduced mal gene expression. Not reflected in this scheme is the dependence of malT expression on the cAMP/CAP complex and the state of PtsG phosphorylation on binding Mlc (or Glk).