Analysis of PhoD^CG-GFP secretion in <i>C</i>. <i>glutamicum</i> wild-type and <i>tat</i> mutant strains.

<p>Cultures of <i>C</i>. <i>glutamicum</i> strains expressing the Tat-dependent PhoD^CG-GFP model protein [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123413#pone.0123413.ref035" target="_blank">35</a>] were fractionated into cells (C) and supernatant (S). Samples of the fractions corresponding to an equal number of cells (i.e. an OD₆₀₀ of 1.0) were subjected to SDS-PAGE and immunoblotting using GFP-specific antibodies. The following strains were analyzed: <i>C</i>. <i>glutamicum</i> wild-type (wt) containing the empty vector pEKEx2 as negative control (lanes 1 and 2), <i>C</i>. <i>glutamicum</i> wild-type (wt) containing plasmid pCGPhoD^CG-GFP (lanes 3 and 4), and the pCGPhoD^CG-GFP-containing <i>C</i>. <i>glutamicum</i> mutant strains Δ<i>tatAC</i> (lanes 5 and 6), Δ<i>tatB</i> (lanes 7 and 8), and Δ<i>tatA/E</i> (lanes 9 and 10). p: PhoD^CG-GFP precursor; asterisk: cytosolic degradation product; m: mature-sized GFP protein.