In Escherichia coli, the DnaK/DnaJ chaperone can control the stability and activity of sigma(32), which is the key factor in heat shock response. Heterologous expression of eukaryotic molecular chaperones protects E. coli from heat stress. Here, we show that BAH1, an E3 ligase from plant that has a similar zinc finger domain to DnaJ, can perform block the effect of DnaK on sigma(32) in Escherichia coli. By constructing a chimeric DnaJ protein, with the J-domain of DnaJ fused to BAH1, we found BAH1 could partially compensate for the DnaJ' zinc finger domain in vivo, and that it was dependent on the zinc finger domain of BAH1. Furthermore, BAH1 could interact with both sigma(32) and DnaK to increase the level of HSPs, such as GroEL, DnaK, and sigma(32). These results suggested that the zinc finger domain was conserved during evolution.