Small heat shock proteins, IbpA and IbpB, are involved in resistances to heat and superoxide stresses in<i>Escherichia coli</i>

Abstract

To investigate the function of Escherichia coli small heat shock proteins, IbpA and IbpB, we constructed ibpA-, ibpB- and ibpAB-overexpressing strains and also an ibpAB-disrupted strain. The ibpA-, ibpB- and ibpAB-overexpressing strains were found to be resistant not only to heat but also to superoxide stress. However, the ibpAB-disrupted strain was not more sensitive to these stresses than the wild-type strain. The heat sensitivity of a rpoH amber mutant was partially suppressed by the overexpression of plac::ibpAB. These results suggest that IbpA and IbpB may be involved in the resistances to heat and oxidative stress.