FIG. 1.

Detection of heat shock proteins produced by E. coli MC4100 (WT) and E. coli A7448 (rpoH⁻). E. coli A7448 transformed with pUC18 (−), pRJ5000 (rpoH₁, indicated as 1), pRJ5002 (rpoH₂, indicated as 2), pRJ5040 (rpoH₃, indicated as 3), or pEC5007 (E. coli rpoH, indicated as E) was grown in the presence of 0.5 mM IPTG. Crude cell extracts were prepared from cells grown at 28°C (0) or heat-shocked cells (heat shock [HS] from 28 to 43°C for 5 or 10 min as indicated) and separated on a SDS–12% polyacrylamide gel. A Coomassie blue-stained gel is shown at the top. The apparent molecular masses (in kilodaltons) of relevant marker proteins are indicated to the left of the gel. Similar gels with suitably diluted samples (1/5, 1/10, 1/3, and 1/15 of the amounts loaded onto the stained gel) were used for immunodetection of the Hsps DnaK, GroEL, GrpE, and IbpA plus IbpB, respectively.