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Balance of ATPase stimulation and nucleotide exchange is not required for efficient refolding activity of the DnaK chaperone
Author(s) -
Groemping Yvonne,
Seidel Ralf,
Reinstein Jochen
Publication year - 2005
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/j.febslet.2005.09.056
Subject(s) - thermus thermophilus , chaperone (clinical) , atpase , biology , complementation , escherichia coli , biochemistry , adenosine triphosphate , microbiology and biotechnology , enzyme , mutant , gene , medicine , pathology
The DnaK system from Thermus thermophilus (DnaK Tth ) exhibits pronounced differences in organisation and regulation to its mesophile counterpart from Escherichia coli (DnaK Eco ). While the ATPase cycle of DnaK Eco is tightly regulated by the concerted action of the two cofactors DnaJ Eco and GrpE Eco , the DnaK Tth system features an imbalance in this cochaperone mediated regulation. GrpE Tth considerably accelerates the ATP/ADP exchange, but DnaJ Tth only slightly stimulates ATPase activity, believed to be a key step for chaperone activity of DnaK Eco . By in vitro complementation assays, we could not detect significant ATPase‐stimulation of orthologous DnaJ Tth · DnaK Eco or DnaJ Eco · DnaK Tth ‐complexes as compared to the DnaK Eco system, although they were nevertheless active in luciferase refolding experiments. Assistance of protein recovery by DnaK thus seems to be uncoupled of the magnitude of DnaJ mediated ATPase‐stimulation.