A Proteomic View of Escherichia coli Metabolic Features

Escherichia coli is an important human pathogen, among others a cause of severe diarrhea diseases and urinary tract infections. The ability to distinguish different pathogenic E. coli subspecies is crucial for correct treatment of the infection. Characterization and quantification of clinical isolates proteomes can provide details of the organisms’ metabolism and specific virulence factors. We performed a systematic quantitative proteomic analysis on a representative selection of 16 pathogenic and 2 commensal E. coli strains, together with 5 pathogenic Shigella strains. The analysis yielded a dataset of more than 4 thousand proteins, with an average of 2 thousand proteins per strain and 980 proteins common to all strains. Statistical comparison of label-free quantitative levels of 750 proteins, which were quantified in all strains, revealed that levels of a majority of the shared proteins vary substantially among specific strains. Theses quantitative protein profiles clearly distinguished E. coli strains from Shigella and largely separated commensal E. coli strains from intestinal and extraintestinal E. coli isolates.