Journal of Gastrointestinal & Digestive System
Open Access

Abstract

Virulent strains of Escherichia coli can cause gastroenteritis, urinary tract infections and neonatal meningitis. E. coli must acquire iron from the host to establish a foothold and colonize the gut. Meanwhile, the biological activity of a cell is performed by protein-protein interactions, and the interaction proteins are commonly assembled of a complex. Knowing a set of protein complexes of a cell, complexome, is therefore essential for an understanding and global vision of cell functions. To visualize and identify protein complexome of E. coli, K-12 under close proximately physiological conditions on a proteomewide scale, cytosolic proteins were analyzed in E. coli by 2-DE native/SDS PAGE combination with mass spectrometry. A total of 49 distinct heteromeric and homomeric protein complexes, involved in metabolism, cellular processes and information processing, were identified, and part of them were well characterized and two, FusA-TufA-Tsf and TnaA-Pflb, were confirmed by co-immnoprecipitation and far Western-blotting analysis, respectively. RpoC-RpsA-Tig-GroL was suggested as a new characterized complex involved in transcription and co-translation folding. Furthermore, the altered protein complexome related to iron-starvation was characterized, showing that sixteen differential proteins belonging to eleven lines were identified. Of the sixteen differential proteins, fourteen were first reported in this study, in which GltA may play an essential role in ferric citrate uptake system, and YbdO, with function not known presently, is tentatively assigned as a new regulator induced by iron-starvation and regulates other protein expression by binding with DNA. This systematic analysis provides new insights into E. coli systems biology.

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