Inhibition of DnaK autophosphorylation by heat shock proteins and polypeptide substrates.
DnaK, the Hsp70 of Escherichia coli, autophosphorylates in vitro. Of the two heat shock proteins that interact with DnaK, GrpE inhibits DnaK phosphorylation, whereas DnaJ has no effect on the reaction. Three synthetic peptides are shown to inhibit DnaK phosphorylation. The potency of a given peptide correlates with its affinity for the DnaK protein. A truncated DnaK that lacks the carboxyl-terminal peptide-binding domain autophosphorylates; this reaction is resistant to the inhibitory peptides. Phosphorylation of the truncated DnaK is still inhibited by GrpE, indicating that the GrpE-binding site resides in the DnaK amino-terminal domain. Thus, DnaK phosphorylation is regulated in vitro, and possibly in vivo, by physiologically relevant substrates and cofactors.
Panagiotidis
C A
CA
Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
Burkholder
W F
WF
Gaitanaris
G A
GA
Gragerov
A
A
Gottesman
M E
ME
Silverstein
S J
SJ
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism
D001426:Bacterial 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; D010750:Phosphoproteins; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli