Pf-cpn20 successfully replaces the function of GroES in <i>E. coli</i>.

<p> Complementation assays were carried out in a strain of <i>E. coli</i>, MGM100, in which expression of endogenous chaperonins (GroEL-GroES) was under strict control of the pBAD promoter. (A) Various controls for the <i>in vivo</i> system at the indicated growth conditions (10⁻² dilution shown). (B and C) Ten-fold-serial dilutions (10⁻² to 10⁻⁷ shown) of <i>E. coli</i> strain MGM100 harboring plasmid pOFX containing GroEL and the indicated co-chaperonin, grown on agar plates in the presence of glucose and IPTG, but no arabinose: B) at 30°C C) at 44°C.