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Role of Escherichia coli heat shock proteins IbpA and IbpB in protection of alcohol dehydrogenase AdhE against heat inactivation in the presence of oxygen

100%

Matuszewska E., Kwiatkowska J., Ratajczak E., Kuczyńska-Wiśnik D., Laskowska E.

issue 1

55-61

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°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 ΔibpAB 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.

Escherichia coli small heat shock proteins IbpA/B enhance activity of enzymes sequestered in inclusion bodies.

86%

Kuczyńska-Wiśnik D., Żurawa-Janicka D., Narkiewicz J., Kwiatkowska J., Lipińska B., Laskowska E.

vol. 51

issue 4

925-931

Escherichia coli small heat shock proteins, IbpA/B, function as molecular chaperones and protect misfolded proteins against irreversible aggregation. IbpA/B are induced during overproduction of recombinant proteins and bind to inclusion bodies in E. coli cells. We investigated the effect of ΔibpA/B mutation on formation of inclusion bodies and biological activity of enzymes sequestered in the aggregates in E. coli cells. Using three different recombinant proteins: Cro-β-galactosidase, β-lactamase and rat rHtrA1 we demonstrated that deletion of the ibpA/B operon did not affect the level of produced inclusion bodies. However, in aggregates containing IbpA/B a higher enzymatic activity was detected than in the IbpA/B-deficient inclusion bodies. These results confirm that IbpA/B protect misfolded proteins from inactivation in vivo.

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2 Acta Biochimica Polonica

1 2009

1 2004

2 Kuczyńska-Wiśnik D.

2 Kwiatkowska J.

2 Laskowska E.

1 Lipińska B.

1 Matuszewska E.

1 Narkiewicz J.

1 Ratajczak E.

1 Żurawa-Janicka D.

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Role of Escherichia coli heat shock proteins IbpA and IbpB in protection of alcohol dehydrogenase AdhE against heat inactivation in the presence of oxygen

Escherichia coli small heat shock proteins IbpA/B enhance activity of enzymes sequestered in inclusion bodies.