title: Disulfide bond formation and activation of Escherichia coli β-galactosidase under oxidizing conditions.
abstract: Escherichia coli β-galactosidase is probably the most widely used reporter enzyme in molecular biology, cell biology, and biotechnology because of the easy detection of its activity. Its large size and tetrameric structure make this bacterial protein an interesting model for crystallographic studies and atomic mapping. In the present study, we investigate a version of Escherichia coli β-galactosidase produced under oxidizing conditions, in the cytoplasm of an Origami strain. Our data prove the activation of this microbial enzyme under oxidizing conditions and clearly show the occurrence of a disulfide bond in the β-galactosidase structure. Additionally, the formation of this disulfide bond is supported by the analysis of a homology model of the protein that indicates that two cysteines located in the vicinity of the catalytic center are sufficiently close for disulfide bond formation.
authors.affiliation: Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Seras-Franzoso
authors.forename: Roman
authors.initials: R
authors.lastname: Affentranger
authors.forename: Mario
authors.initials: M
authors.lastname: Ferrer-Navarro
authors.forename: Xavier
authors.initials: X
authors.lastname: Daura
authors.forename: Antonio
authors.initials: A
authors.lastname: Villaverde
authors.forename: Elena
authors.initials: E
authors.lastname: García-Fruitós
mesh_terms: D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry* / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D016296:Mutagenesis; D010084:Oxidation-Reduction; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship; D001616:beta-Galactosidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D004220:Disulfides; D029968:Escherichia coli Proteins; D001616:beta-Galactosidase; D003545:Cysteine