title: Mass-spectral analysis of human interferon-gamma and chloramphenicol acetyltransferase I produced in two Escherichia coli strains.
abstract: Recombinant human interferon-gamma and chloramphenicol acetyltransferase I were isolated from two Escherichia coli strains, E. coli LE329 and E. coli XL1-blue and characterized by electrospray ionization mass spectrometry (ESI-MS). The ESI-MS analysis showed higher masses in comparison with the theoretically calculated for both proteins as well as unexpected molecular heterogeneity. The ESI-MS spectral patterns of the proteins depended on the host strain used and were more heterogenous for the proteins isolated from E. coli LE392. One of the proteins (human interferon-gamma obtained from E. coli XL1-blue) was further subjected to BrCN cleavage. The ESI-MS analysis of the polypeptide mixture revealed shift in the molecular mass for two peptides including the last 26 amino acids of the human interferon-gamma molecule.
authors.affiliation: Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors.forename: A
authors.initials: A
authors.lastname: Vassileva-Atanassova
authors.forename: T
authors.initials: T
authors.lastname: Niwa
authors.forename: R
authors.initials: R
authors.lastname: Mironova
authors.forename: I
authors.initials: I
authors.lastname: Ivanov
mesh_terms: D001709:Biotechnology / Q000379:methods; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis* / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis* / Q000235:genetics*; D013058:Mass Spectrometry; D010957:Plasmids; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000032:analysis / Q000096:biosynthesis
chemical_list: D011994:Recombinant Proteins; D007371:Interferon-gamma; D015500:Chloramphenicol O-Acetyltransferase