FIG 5 .

Effect of the Ffh M domain on the stability of LacY-GFP. (A) E. coli IY228 harboring plasmids encoding arabinose-inducible M and carrying ffs or empty vector were induced with arabinose, and then IPTG was added to induce expression of LacY-GFP. The cells were pulse-labeled for 3 min with [³⁵S]methionine and [³⁵S]cysteine and chased with an excess of methionine and cysteine. Equal samples were withdrawn at the indicated time points, and LacY-GFP was immunoprecipitated using anti-GFP antibodies. The precipitates were solubilized in 50 µl SDS sample buffer, and 25 µl was loaded on SDS-PAGE gel (12%), which was then dried and subjected to autoradiography. (B) The amount of labeled LacY-GFP was quantified by densitometry, and the data shown are averages of results from three independent experiments.