SDS-PAGE of the purification step by anion exchange chromatography (MonoQ 5/50 GL column).

<p>(A) Protein purification from MC4100 cells cultivated in TGYEP medium supplemented with 2 µM sodium selenite and 2 µM sodium molybdate; 12% (w/v) resolving gel; M: molecular weight marker; L: sample applied to the column; F, column flow-through; 1–5: elution fractions. (B) Protein purification from MC4100 cells cultivated in TGYEP medium supplemented with 100 µM sodium selenite and 100 µM sodium molybdate; 8% (w/v) resolving gel; M: molecular weight marker; L1: sample loaded on the size exclusion column; L2:sample loaded on the anion exchange column; 1–4: elution fractions from the anion-exchange column. Polypeptides labeled I though VIII were those identified by mass spectrometry and are listed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061913#pone-0061913-t001" target="_blank">Table 1</a>.