Disassembly of the Coliphage λ Replication Complex Due to Heat Shock Induction of thegroEOperon

Abstract

AbstractWe have found previously that, in contrast to the free O initiator protein of λ phage or plasmid rapidly degraded by theEscherichia coliClpP/ClpX protease, the λO present in the replication complex (RC) is protected from proteolysis. In amino acid-starvedE. coli relAcells, a temperature shift from 30 to 43° did not affect RC integrity, as judged from the unchanged level of stable λO observed; however, the same temperature shift in a complete medium resulted in the decay of this λO fraction, which suggested disassembly of the RC. Examination of this phenomenon revealed that for λ RC disassembly, heat shock induction of thegroEoperon, coding for molecular chaperones of the Hsp60 class, is indispensable. Heat shock induction of thegroEoperon present on a multicopy plasmid inhibited the growth of infecting phage