Activity of the Hsp70 chaperone complex--DnaK, DnaJ, and GrpE--in initiating phage lambda DNA replication by sequestering and releasing lambda P protein.
Initiation of DNA replication by phage lambda requires the ordered assembly and disassembly of a specialized nucleoprotein structure at the origin of replication. In the disassembly pathway, a set of Escherichia coli heat shock proteins termed the Hsp70 complex--DnaK, DnaJ, and GrpE--act with ATP to release lambda P protein from the nucleo-protein complex, freeing the DnaB helicase for its DNA-unwinding reaction. To investigate the mechanism of the release reaction, we have examined the interaction between P and the three heat shock proteins by glycerol gradient sedimentation and gel electrophoresis. We have discovered an ATP-dependent ternary interaction between P, DnaK, and DnaJ; this P.DnaK.DnaJ complex is dissociated by GrpE. We have concluded that the function of the Hsp70 complex in sequestering and releasing P protein provides for the critical step in the disassembly pathway. Based on our data and other work on protein folding, the formation of the P.DnaK.DnaJ complex might involve a conformational shift to a folding intermediate of P.
Hoffmann
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Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720.
Lyman
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Petit
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Echols
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D001426:Bacterial Proteins / Q000378:metabolism*; D010582:Bacteriophage lambda / Q000235:genetics*; D018833:Chaperonins; D004265:DNA Helicases; D004261:DNA Replication; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D053488:DnaB Helicases; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D046911:Macromolecular Substances; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
D001426:Bacterial Proteins; C024013:DNA replication complex protein, Bacteriophage lambda; D004279:DNA, Viral; D004268:DNA-Binding Proteins; C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; C068113:GrpE protein, Bacteria; C489400:GrpE protein, E coli; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D011506:Proteins; D014764:Viral Proteins; D018833:Chaperonins; C063842:dnaK protein, E coli; D004265:DNA Helicases; D053488:DnaB Helicases