Identification of In Vivo Substrate Proteins of the Periplasmic Disulfide Bond Oxidase DsbA

<div><p>(A) Colored overlay of the stained 2D gel (shown in green) and the phosphor image (shown in red) of differentially trapped protein extract from exponentially growing E. coli wild-type cells. Proteins with a high ¹⁴C activity/protein ratio appear red, while proteins with a low ratio appear green. Proteins that were found to have significantly lower ratio of ¹⁴C activity/protein in the <i>dsbA</i>::kan strain (B and C) are labeled.</p> <p>(B) Overlay of the stained 2D gel (shown in green) and the phosphor image (shown in red) of a differentially trapped protein extract from exponentially growing <i>dsbA</i>::kan cells. Proteins that were found to have a significantly lower ¹⁴C activity/protein ratio in <i>dsbA</i>::kan cells than in wild-type strain (A) are marked with an arrowhead. A circle marks the position of DsbA on the wild-type gel.</p> <p>(C) Overlay of the stained 2D gel (shown in green) and the phosphor image (shown in red) of a differentially trapped protein extract from <i>E. coli dsbA</i>::kan cells growing under oxygen limitation. Arrowheads label proteins that were found to have a significantly lower ¹⁴C activity/protein ratio than the wild-type strain grown under oxygen limitation. A circle marks the position of DsbA on the wild-type gel.</p>