Calf thymus Hsc70 and Hsc40 can substitute for DnaK and DnaJ function in protein renaturation but not in bacteriophage DNA replication.
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.
Ziemienowicz
A
A
Department of Veterinary Biochemistry, University of Zürich, Zurich, Switzerland. ziemien@biotech.univ.gda.pl
Konieczny
I
I
Hübscher
U
U
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
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