Escherichia coli heat-shock proteins IbpA/B are involved in resistance to oxidative stress induced by copper.
The small heat-shock proteins IbpA/B are molecular chaperones that bind denatured proteins and facilitate their subsequent refolding by the ATP-dependent chaperones DnaK, DnaJ, GrpE and ClpB. In this report, we demonstrate that IbpA/B participate in the defence against copper-induced stress under aerobic conditions. In the presence of oxygen, DeltaibpA/B cells exhibit increased sensitivity to copper ions and accumulate elevated amounts of oxidized proteins, while under oxygen depletion, the DeltaibpA/B mutation has no effect on copper tolerance. This indicates that IbpA/B protect Escherichia coli cells from oxidative damage caused by copper. We show that AdhE, one of the proteins exposed to oxidation, is protected by IbpA/B against copper-mediated inactivation both in vivo and in vitro.
Department of Biochemistry, University of Gdańsk, Kładki 24, 80-952 Gdańsk, Poland.
Ewelina
E
Matuszewska
Department of Biochemistry, University of Gdańsk, Kładki 24, 80-952 Gdańsk, Poland.
Joanna
J
Kwiatkowska
Department of Biochemistry, University of Gdańsk, Kładki 24, 80-952 Gdańsk, Poland.
Dorota
D
Kuczyńska-Wiśnik
Department of Biochemistry, University of Gdańsk, Kładki 24, 80-952 Gdańsk, Poland.
Ewa
E
Laskowska
D000332:Aerobiosis; D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D000693:Anaerobiosis; D002384:Catalysis; D003300:Copper / Q000633:toxicity*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress
D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C097578:IbpA protein, E coli; C097579:IbpB protein, E coli; D009097:Multienzyme Complexes; D003300:Copper; D000426:Alcohol Dehydrogenase; C068383:adhE protein, E coli; D000445:Aldehyde Oxidoreductases