Evran, Serap and Telefoncu, Azmi and Sterner, Reinhard (2012) Directed evolution of ()(8)-barrel enzymes: establishing phosphoribosylanthranilate isomerisation activity on the scaffold of the tryptophan synthase -subunit. PROTEIN ENGINEERING DESIGN & SELECTION, 25 (6). pp. 285-293. ISSN 1741-0126,
Full text not available from this repository. (Request a copy)Abstract
Phosphoribosylanthranilate (PRA) isomerase (TrpF) and tryptophan synthase -subunit (TrpA) are ()(8)-barrel enzymes that are involved in the biosynthesis of tryptophan. They contain a conserved phosphate binding site, which indicates a common evolutionary origin. In order to experimentally back this hypothesis, we have established TrpF activity on the scaffold of TrpA from Salmonella typhimurium using protein engineering. Based on the superposition of crystal structures with bound ligands, two residues in the active site of TrpA were replaced with catalytic residues from TrpF using site-directed mutagenesis. This TrpA variant as well as wild-type TrpA were each subjected to random mutagenesis using error-prone PCR. The two resulting trpA gene libraries were used to transform an auxotrophic Escherichia coli trpF deletion strain, and TrpA variants with PRA isomerisation activity were isolated by in vivo complementation. The amino acid substitutions of the selected TrpA variants were recombined by DNA shuffling, again followed by complementation in vivo. Several TrpA variants were produced in E. coli and purified, and their catalytic TrpF activities were determined in vitro by steady-state enzyme kinetics. Our results support that TrpA and TrpF have evolved by gene duplication and diversification from each other or a common predecessor, and provide insights into the minimum requirements for the catalysis of PRA isomerisation.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DIFFERENT METABOLIC PATHWAYS; TIM-BARREL FOLD; (BETA-ALPHA)(8)-BARREL ENZYMES; THERMOTOGA-MARITIMA; ESCHERICHIA-COLI; INDOLE-3-GLYCEROL PHOSPHATE; ANTHRANILATE ISOMERASE; CATALYTIC-ACTIVITY; EFFICIENT ENZYMES; PROTEIN EVOLUTION; ()(8)-barrel; enzyme evolution; protein design; tryptophan biosynthesis |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie > Prof. Dr. Reinhard Sterner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 13 May 2020 05:55 |
| Last Modified: | 13 May 2020 05:55 |
| URI: | https://pred.uni-regensburg.de/id/eprint/18669 |
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