DISASSEMBLY OF THE COLIPHAGE-LAMBDA REPLICATION COMPLEX DUE TO HEAT-SHOCK INDUCTION OF THE GROE OPERON

We have found previously that in contrast to the free O initiator prot ein of lambda phage or plasmid rapidly degraded by the Escherichia col i ClpP/ClpX protease, the lambda O present in the replication complex (RC) is protected from proteolysis. In amino acid-starved E. coli relA cells, a temperature shift from 30 to 43 degrees did not affect RC in tegrity, as judged from the unchanged level of stable lambda O observe d; however, the same temperature shift in a complete medium resulted i n the decay of this lambda O fraction, which suggested disassembly of the RC. Examination of this phenomenon revealed that for lambda RC dis assembly, heat shock induction of the groE operon, coding for molecula r chaperones of the Hsp60 class, is indispensable. Heat shock inductio n of the groE operon present on a multicopy plasmid inhibited the grow th of infecting phage. (C) 1996 Academic Press, Inc.