title: Refolding and purification of Cephalosporium acremonium deacetoxycephalosporin C synthetase/hydroxylase from granules of recombinant Escherichia coli.
abstract: The gene for bifunctional deacetoxycephalosporin C synthetase/hydroxylase of Cephalosporium acremonium was cloned and overexpressed as an insoluble and inactive enzyme in granules of recombinant Escherichia coli. About 40-60% of expected synthetase activity along with 50-80% protein purity could be recovered directly from granular extracts with only a single empirically optimized refolding step. Further purification to homogeneity was achieved by a single anion-exchange-chromatographic step in the presence of denaturing concentrations of urea. The main obstacle to converting the homogeneous unfolded protein into the active enzyme was a urea-dependent aggregation during refolding that led to irreversible enzyme inactivation. Information obtained from refolding studies using gel-filtration HPLC, fluorescence spectroscopy and disulphide analysis led to an optimal enzyme refolding scheme that resulted in a highly active (i.e. 65-75% of the expected activity) and moderately stable fungal synthetase/hydroxylase.
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Ghag
authors.forename: D N
authors.initials: DN
authors.lastname: Brems
authors.forename: T C
authors.initials: TC
authors.lastname: Hassell
authors.forename: W K
authors.initials: WK
authors.lastname: Yeh
mesh_terms: D000164:Acremonium / Q000201:enzymology*; D004220:Disulfides / Q000737:chemistry; D004795:Enzyme Stability; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D019751:Intramolecular Transferases; D007535:Isomerases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008956:Models, Chemical; D046915:Penicillin-Binding Proteins; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D004220:Disulfides; D046915:Penicillin-Binding Proteins; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds; D007535:Isomerases; D019751:Intramolecular Transferases; C038371:deacetoxycephalosporin C synthetase