Synthesis of the arabinose operon regulator protein in a cell-free system

Summary A DNA-directed cell-free system which synthesizes L-ribulokinase coded by the L-arabinose operon, ara OIBAD, has been developed. L-arabinose is required for the expression of this operon and, in addition, cyclic AMP and guanosine-tetraphosphate are needed for optimal synthesis. The ara C gene product is also required and can be supplied either by de novo synthesis in the cell-free system or added back from extracts of whole cells. Evidence is presented that the C gene product is highly susceptible to protease attack.