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Autostimulation of the DnaK (HSP 70) ATPase of Escherichia coli
Author(s) -
Richarme Gilbert,
Kohiyama Masamichi
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81585-n
Subject(s) - atpase , escherichia coli , atp hydrolysis , chaperone (clinical) , trypsin , biochemistry , chemistry , biology , microbiology and biotechnology , enzyme , medicine , pathology , gene
The ATPase activity of DnaK, the 70‐kDa chaperone of Escherichia coli , is stimulated by an unfolded protein. However, the stimulation of the DnaK ATPase by unfolded bovine pancreatic trypsin inhibitor can only be observed at low DnaK protein concentrations. At higher DnaK concentrations, the ATPase activity of DnaK cannot be stimulated by the addition of unfolded bovine pancreatic trypsin inhibitor. This is a consequence of the autostimulation of the DnaK ATPase at higher DnaK concentrations. The autostimulation of DnaK is reflected by a non‐linear dependence of ATP hydrolysis on DnaK concentration. Furthermore, DnaK exists as a mixture of monomers and dimers in equilibrium, and the dimers dissociate into monomers in the presence of ATP.