title: Proteome analysis of Escherichia coli W3110 expressing an heterologous sigma factor.
abstract: 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.
authors.affiliation: Section of Biochemistry, Department of Molecular Biology, University of Siena, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Baglioni
authors.forename: Luca
authors.initials: L
authors.lastname: Bini
authors.forename: Sabrina
authors.initials: S
authors.lastname: Liberatori
authors.forename: Vitaliano
authors.initials: V
authors.lastname: Pallini
authors.forename: Laura
authors.initials: L
authors.lastname: Marri
mesh_terms: D000595:Amino Acid Sequence; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D007091:Image Processing, Computer-Assisted; D008969:Molecular Sequence Data; D009154:Mutation; D010449:Peptide Mapping; D033903:Periplasmic Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010544:Peroxidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020543:Proteome / Q000032:analysis* / Q000378:metabolism; D040901:Proteomics; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D029968:Escherichia coli Proteins; D033903:Periplasmic Proteins; D020543:Proteome; D012808:Sigma Factor; D010544:Peroxidases; C097049:Tpx protein, E coli