title: Calf thymus Hsc70 and Hsc40 can substitute for DnaK and DnaJ function in protein renaturation but not in bacteriophage DNA replication.
abstract: Calf thymus (ct) Hsc70 has been shown previously to reactivate heat-inactivated prokaryotic and eukaryotic enzymes, while DnaK was able to reactivate solely prokaryotic enzymes. Here, we report on isolation from calf thymus of a DnaJ homolog, ctHsc40, and on testing of its cooperative function in three different assays: (i) reactivation of heat-inactivated DNA polymerases, (ii) stimulation of the ATPase activity of ctHsc70 chaperone, and (iii) replication of bacteriophage lambda DNA. Surprisingly, ctHsc70/ctHsc40 chaperones were found to reactivate the denatured prokaryotic and eukaryotic enzymes but not to promote bacteriophage lambda DNA replication, suggesting species specificity in DNA replication.
authors.affiliation: Department of Veterinary Biochemistry, University of Zürich, Zurich, Switzerland. ziemien@biotech.univ.gda.pl
authors.forename: A
authors.initials: A
authors.lastname: Ziemienowicz
authors.forename: I
authors.initials: I
authors.lastname: Konieczny
authors.forename: U
authors.initials: U
authors.lastname: Hübscher
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D010582:Bacteriophage lambda / Q000378:metabolism; D002417:Cattle; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins; D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D066298:In Vitro Techniques; D020673:Protein Renaturation; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D013045:Species Specificity
chemical_list: C494635:DnaJ protein, E coli; C400502:Dnajb5 protein, mouse; D029968:Escherichia coli Proteins; D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D011506:Proteins; D004259:DNA-Directed DNA Polymerase; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli