title: Autoprocessing of the HIV-1 protease using purified wild-type and mutated fusion proteins expressed at high levels in Escherichia coli.
abstract: Various constructs of the human immunodeficiency virus, type 1 (HIV-1) protease containing flanking Pol region sequences were expressed as fusion proteins with the maltose-binding protein of the malE gene of Escherichia coli. The full-length fusion proteins did not exhibit self-processing in E. coli, thereby allowing rapid purification by affinity chromatography on cross-linked amylose columns. Denaturation of the fusion protein in 5 M urea, followed by renaturation, resulted in efficient site-specific autoprocessing to release the 11-kDa protease. Rapid purification involving two column steps gave an HIV-1 protease preparations of greater than 95% purity (specific activity approximately 8500 pmol.min-1.micrograms protease-1) with an overall yield of about 1 mg/l culture. Incubation of an inactive mutant protease fusion protein with the purified wild-type protease resulted in specific trans cleavage and release of the mutant protease. Analysis of products of the HIV-1 fusion proteins containing mutations at either the N- or the C-terminal protease cleavage sites indicated that blocking one of the cleavage sites influences the cleavage at the non-mutated site. Such mutated full-length and truncated protease fusion proteins possess very low levels of proteolytic activity (approximately 5 pmol.min-1.micrograms protein-1).
authors.affiliation: Division of Cancer Biology and Diagnosis, National Cancer Institute, National Institutes of Health, Bethesda, MD.
authors.forename: J M
authors.initials: JM
authors.lastname: Louis
authors.forename: R A
authors.initials: RA
authors.lastname: McDonald
authors.forename: N T
authors.initials: NT
authors.lastname: Nashed
authors.forename: E M
authors.initials: EM
authors.lastname: Wondrak
authors.forename: D M
authors.initials: DM
authors.lastname: Jerina
authors.forename: S
authors.initials: S
authors.lastname: Oroszlan
authors.forename: P T
authors.initials: PT
authors.lastname: Mora
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D005822:Genetic Vectors; D016333:HIV Protease / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015497:HIV-1 / Q000201:enzymology* / Q000235:genetics; D007700:Kinetics; D008320:Maltose / Q000378:metabolism; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009004:Monosaccharide Transport Proteins; D016297:Mutagenesis, Site-Directed; D033902:Periplasmic Binding Proteins; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D013379:Substrate Specificity
chemical_list: D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; D008320:Maltose; D016333:HIV Protease