FIGURE 4.

Comparison of the TM4-Cx45CT expression profile obtained from E. coli strain C41(DE3) with the pLysS plasmid in LB and minimal media. C41(DE3)pLysS transformed with the TM4-Cx45CT plasmid was grown in LB medium (lanes 2 and 3), ¹⁵N-labeled M63 minimal medium (lanes 5 and 6), and ¹⁵N-labeled M63 minimal medium supplemented with 1 g ¹⁵N-ISOGRO/L medium (lanes 8 and 9). Lane 1 contains the Precision Plus Protein All Blue Standards molecular mass marker (Bio-Rad) and lanes 4 and 7 are blank. Samples were collected just prior to (uninduced, U) and 4 h after IPTG induction (I), as noted. A total of 500 μL samples with an Abs_{600 nm} at 0.5 were pelleted and resuspended in 30 μL of 6× SDS loading buffer. Equal amounts of total protein (7 μL) were ran on a 15% SDS-PAGE gel and stained with Coomassie Blue. The TM4-Cx45CT has an expected molecular mass of ~22 kDa, indicated by the arrow.