Evaluation of two proteomics technologies used to screen the membrane proteomes of wild-type Corynebacterium glutamicum and an L-lysine-producing strain.

The membrane proteomes of a wild-type Corynebacterium glutamicum and an L-lysine-producing strain were quantitatively analyzed by two complementary proteomics techniques -- anion exchange chromatography AIEC/SDS-PAGE and 16BAC-PAGE/SDS-PAGE -- and the results were compared. Although both techniques allow for the fast screening of differences in protein abundance, AIEC/SDS-PAGE was superior to 16BAC-PAGE/SDS-PAGE with respect to protein separation, it was more suitable for relative protein quantification, and allowed more differentially regulated proteins to be detected (the succinate dehydrogenase complex, an ABC-type cobalamin/Fe(3+) siderophore transport system, the maltose binding protein, and a subunit of the cytochrome bc-aa(3) supercomplex were upregulated, while a periplasmic component of an ABC-type transporter and an iron-regulated ABC-type transporter were downregulated in the producer). The results indicate the important role of tricarboxylic acid cycle enzymes as well as the adaptation of transport processes in L-lysine-producing cells. Since the only genetic differences between the wild type and the L-lysine producer occur between four central metabolic enzymes in the cytoplasm, our study illustrates the complex effects of metabolic engineering on cell physiology and the power of the new AIEC/SDS-PAGE proteomics approach to detect these effects.