Overexpression of the lmo1438 gene in L. monocytogenes. Membrane proteins were isolated from L. monocytogenes pAKB (lane 1) and L. monocytogenes pAKB-lmo1438 (lane 2) that had been grown at 37°C to exponential phase in BHI broth supplemented with nisin to a final concentration of 15 μg/ml. Proteins were separated by SDS-PAGE and stained with Coomassie brilliant blue. LMW - Protein Molecular Weight Marker. The position of the band corresponding to Lmo1438 is indicated by an arrow.