title: Role of Escherichia coli heat shock proteins IbpA and IbpB in protection of alcohol dehydrogenase AdhE against heat inactivation in the presence of oxygen.
abstract: Escherichia coli small heat shock proteins IbpA and IbpB are molecular chaperones that bind denatured proteins and facilitate their subsequent refolding by the ATP-dependent chaperones DnaK/DnaJ/GrpE and ClpB. In vivo, the lack of IbpA and IbpB proteins results in increased protein aggregation under severe heat stress or delayed removal of aggregated proteins at recovery temperatures. In this report we followed the appearance and removal of aggregated alcohol dehydrogenase, AdhE, in E. coli submitted to heat stress in the presence of oxygen. During prolonged incubation of cells at 50 degrees C, when AdhE was progressively inactivated, we initially observed aggregation of AdhE and thereafter removal of aggregated AdhE. In contrast to previous studies, the lack of IbpA and IbpB did not influence the formation and removal of AdhE aggregates. However, in DeltaibpAB cells AdhE was inactivated and oxidized faster than in wild type strain. Our results demonstrate that IbpA and IbpB protected AdhE against thermal and oxidative inactivation, providing that the enzyme remained soluble. IbpA and IbpB were dispensable for the processing of irreversibly damaged and aggregated AdhE.
authors.affiliation: Department of Biochemistry, Faculty of Biotechnology, University of Gdańsk, Gdańsk, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Matuszewska
authors.forename: Joanna
authors.initials: J
authors.lastname: Kwiatkowska
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Ratajczak
authors.forename: Dorota
authors.initials: D
authors.lastname: Kuczyńska-Wiśnik
authors.forename: Ewa
authors.initials: E
authors.lastname: Laskowska
mesh_terms: D000426:Alcohol Dehydrogenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D029968:Escherichia coli Proteins / Q000502:physiology*; D006360:Heat-Shock Proteins / Q000502:physiology*; D006358:Hot Temperature; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C097578:IbpA protein, E coli; C097579:IbpB protein, E coli; D009097:Multienzyme Complexes; D000426:Alcohol Dehydrogenase; C068383:adhE protein, E coli; D000445:Aldehyde Oxidoreductases; D010100:Oxygen