Proteomics 2014, 14, 2369–2388 DOI 10.1002/pmic.2014 TUTORIAL Basics of mass spectrometry based metabolomics ´ erique Fred ´ Courant1,2, Jean-Philippe Antignac2,3, Gaud Dervilly-Pinel2 and Bruno Le Bizec2 1 Department of Environmental Sciences and Public Health, University of Montpellier 1, UMR 5569 Hydrosciences, Montpellier, France 2 ´ Laboratoire d’Etude des Residus et.
The recombinant plasmid pASK18 carries a Streptomyces DNA fragment which includes an open reading frame, designated psfS (putative sigma factor, Streptomyces), as its putative product showed a high degree of similarity with RNA polymerase sigma factors. Previous results showed that PsfS causes transcription initiation within the bgl operon promoter‐silencer region in Escherichia coli K12. In this study a proteomic approach has been applied in order to perform a comparative analysis of E. coli K12 W3110 wild‐type, W3110 (pASK18) and a W3110 Bgl + spontaneous mutant. Either by qualitative or quantitative analysis, no significant difference was observed between the proteomes of W3110 and its Bgl+ derivative, while W3110 (pASK18) showed an altered profile by both analyses. Fourteen out of the 37 protein spots showing a different expression level in E. Coli W3110 harboring pASK18 were identified by peptide mass fingerprinting. Among the proteins identified, thiol peroxidase (Tpx) was the only one up‐regulated.
The possible involvement of bgl and tpx in the survival of the pathogen E. Coli during infection is discussed.