Heat shock protein-mediated disassembly of nucleoprotein structures is required for the initiation of bacteriophage lambda DNA replication.

摘要: Abstract Three Escherichia coli heat shock proteins, DnaJ, DnaK, and GrpE, are required for replication of the bacteriophage lambda chromosome in vivo. We show that GrpE protein is not initiation DNA vitro when concentration DnaK sufficiently high. does, however, greatly potentiate action process reduced to a subsaturating level. demonstrate accompanying articles (Alfano, C. McMacken, R. (1989) J. Biol. Chem. 264, 10699-10708; Dodson, M., R., Echols, H. 10719-10725) DnaJ bind prepriming nucleoprotein structures assembled at origin (ori lambda). Binding completes ordered assembly an ori complex also contains O P initiators E. DnaB helicase. With addition ATP, proteins mediate partial disassembly complex, largely removed from template. Concomitantly, on supercoiled plasmid templates, intrinsic helicase activity activated initiates localized unwinding duplex, thereby preparing template priming chain elongation. infer our results function normal metabolism promote ATP-dependent unfolding reactions. provide evidence neither nor play direct role propagation forks vitro.