Regulation of synthesis of a major outer membrane protein: cyclic AMP represses Escherichia coli protein III synthesis.

Cyclic AMP is the effector molecule for both positive and negative control of synthesis of several Escherichia coli proteins. Among the latter is the major outer membrane protein III. The control mechanism occurs at the level of transcription and involves the cyclic AMP receptor protein. The repressing system is saturated at lower concentrations of cyclic AMP than is the positive control system.