39 research outputs found
Overexpression, solubilization and refolding of a genetically engineered derivative of the penicillin-binding protein 3 of Escherichia coli K12.
Replacement of the amino-terminal 40-amino-acid region of the 588-amino-acid precursor of the membrane-bound penicillin-binding protein 3 (PBP3) by the decapeptide MKGKEFQAWI was carried out by altering the amino-coding end of the ftsI gene. Insertion of the modified gene into a runaway-replication plasmid under the control of a fused lpp promoter and lac promoter/operator, resulted in the overexpression by Escherichia coli of the modified PBP3 (designated PBP3**) in the cytoplasm. About 80% of the accumulated PBP3** underwent sequestration in the form of insoluble protein granules that were isolated by cell breakage or cell lysis. After selective removal of contaminants by an EDTA-lysozyme/DNase (deoxyribonuclease)/Nonidet extraction, treatment of the granules with guanidinium chloride followed by dialysis against buffer containing 0.5 M NaCl yielded a refolded, water-soluble PBP3**, which, upon chromatography on Superose 12, exhibited the expected 60,000 molecular mass. The refolded PBP3** bound benzylpenicillin in a 1 to 1 molar ratio, was highly sensitive to aztreonam and showed the same degree of thermostability, in terms of penicillin-binding capacity, as the parent, membrane-bound PBP3, suggesting that protein refolding occurred with formation of the correct intramolecular interactions. Two to three mg of refolded PBP3** can be obtained from 1 litre of culture of the overproducing strain
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Impact of Post-Prostatectomy Prostate Specific Antigen (PSA) Kinetics on Outcomes of Salvage Radiotherapy
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External Beam Radiotherapy Plus Long-Term ADT Versus Combination Brachytherapy Plus Short-Term ADT for High Risk Prostate Cancer: A Network Meta-Analysis of Randomized Trials
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The Impact of Persistently Elevated PSA after Prostatectomy in Men with Recurrent Prostate Cancer in NRG Oncology/RTOG 9601
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