Bastian Feifel

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DnaK, a Hsp70 homolog of Escherichia coli, together with its co-chaperones DnaJ and GrpE protects denatured proteins from aggregation and promotes their refolding by an ATP-consuming mechanism. DnaJ not only stimulates the gamma-phosphate cleavage of DnaK-bound ATP but also binds polypeptide substrates on its own. Unfolded polypeptides, such as denatured(More)
Mitochondrial hsp70 (mhsp70) is a key component in the import and folding of mitochondrial proteins. In both processes, mhsp70 cooperates with the mitochondrial nucleotide exchange factor mGrpE (also termed Mge1p). In this work we have characterized the self-association of purified mhsp70, the interaction of mhsp70 with isolated mGrpE and protein substrate,(More)
During protein import into mitochondria, matrix-localized mitochondrial hsp70 (mhsp70) interacts with the inner membrane protein Tim44 to pull a precursor across the inner membrane. We have proposed that the Tim44-mhsp70 complex functions as an ATP-dependent "translocation motor" that exerts an inward force on the precursor chain. To clarify the role of ATP(More)
Potassium ions stabilize the DnaK.ADP complex that forms on incubation of nucleotide-free DnaK with ADP or ATP. Generation of the crystallographically defined Mg2+ cluster [Wilbanks, S.M. & McKay, D.B. (1995) J. Biol. Chem. 270, 2251-2257], in which two K+ and the nucleotide are bound together with Mg2+ in the ATPase site, appears to be essential for the(More)
The molecular chaperone DnaK, the Hsp70 homolog of Escherichia coli, binds hydrophobic polypeptide segments in extended conformation. The co-chaperone DnaJ (Hsp40) has been reported to bind native and denatured proteins as well as peptides. We tested pseudo-peptides of D-amino acids as ligands for both chaperones. In comparison to the parent all-L peptide,(More)
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