Fig. 5.
Assembly of DegP cages is not required for high-temperature cell survival. (A) E. coli encoding wild-type DegP, DegPY444A, DegPΔlinker, or DegP+20_linker at the standard chromosomal locus expressed similar levels of DegP protein. Strains were grown to log phase in LB broth at 37 °C, and equivalent numbers of cells were lysed and separated by SDS/PAGE. DegP was identified by Western blotting using an anti-DegP antibody. A ΔdegP strain expressed no DegP. All strains expressed comparable levels of a cross-reacting lower molecular-weight protein. (B) Strains expressing wild-type DegP, DegPY444A, DegPΔlinker, or DegP+20_linker exhibited similar overnight growth on LB agar plates at 37 and 47 °C. The ΔdegP strain grew normally at 37 °C but was inviable at 47 °C.