The export of colicin A and of colicin E1 is not equally affected in both secA and secY mutants of E. Echerichia coli: release of colicin A occurs slowly while that of colicin E1 is blocked. Processing and functioning of Cal, the colicin A lysis protein, seem to be slightly or not at all modified in these mutants, whereas synthesis and assembly of CelA, the colicin E1 lysis protein, are highly inhibited. These variations observed in the dependence of the two lysis proteins on secA and secY gene products are interpreted as being either the cause or the consequence of the differences observed in their rate of biogenesis.
