1
|
Graf MMH, Sucharitakul J, Bren U, Chu DB, Koellensperger G, Hann S, Furtmüller PG, Obinger C, Peterbauer CK, Oostenbrink C, Chaiyen P, Haltrich D. Reaction of pyranose dehydrogenase from Agaricus meleagris with its carbohydrate substrates. FEBS J 2015; 282:4218-41. [PMID: 26284701 PMCID: PMC4950071 DOI: 10.1111/febs.13417] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 08/04/2015] [Accepted: 08/13/2015] [Indexed: 01/25/2023]
Abstract
Monomeric Agaricus meleagris pyranose dehydrogenase (AmPDH) belongs to the glucose-methanol-choline family of oxidoreductases. An FAD cofactor is covalently tethered to His103 of the enzyme. AmPDH can double oxidize various mono- and oligosaccharides at different positions (C1 to C4). To study the structure/function relationship of selected active-site residues of AmPDH pertaining to substrate (carbohydrate) turnover in more detail, several active-site variants were generated, heterologously expressed in Pichia pastoris, and characterized by biochemical, biophysical and computational means. The crystal structure of AmPDH shows two active-site histidines, both of which could take on the role as the catalytic base in the reductive half-reaction. Steady-state kinetics revealed that His512 is the only catalytic base because H512A showed a reduction in (kcat /KM )glucose by a factor of 10(5) , whereas this catalytic efficiency was reduced by two or three orders of magnitude for His556 variants (H556A, H556N). This was further corroborated by transient-state kinetics, where a comparable decrease in the reductive rate constant was observed for H556A, whereas the rate constant for the oxidative half-reaction (using benzoquinone as substrate) was increased for H556A compared to recombinant wild-type AmPDH. Steady-state kinetics furthermore indicated that Gln392, Tyr510, Val511 and His556 are important for the catalytic efficiency of PDH. Molecular dynamics (MD) simulations and free energy calculations were used to predict d-glucose oxidation sites, which were validated by GC-MS measurements. These simulations also suggest that van der Waals interactions are the main driving force for substrate recognition and binding.
Collapse
Affiliation(s)
- Michael M H Graf
- Food Biotechnology Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Urban Bren
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
- Laboratory for Physical Chemistry and Chemical Thermodynamics, Faculty of Chemistry and Chemical Technology, University of Maribor, Slovenia
| | - Dinh Binh Chu
- Division of Analytical Chemistry, Department of Chemistry, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
- School of Chemical Engineering, Department of Analytical Chemistry, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Gunda Koellensperger
- Institute of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Austria
| | - Stephan Hann
- Division of Analytical Chemistry, Department of Chemistry, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
| | - Paul G Furtmüller
- Division of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
| | - Christian Obinger
- Division of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
| | - Clemens K Peterbauer
- Food Biotechnology Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
| | - Chris Oostenbrink
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
| | - Pimchai Chaiyen
- Department of Biochemistry and Center of Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Dietmar Haltrich
- Food Biotechnology Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences Vienna (BOKU), Austria
| |
Collapse
|
2
|
Macouzet M, Simpson BK, Lee BH. Expression of a cold-adapted fish trypsin in Pichia pastoris. FEMS Yeast Res 2005; 5:851-7. [PMID: 15925313 DOI: 10.1016/j.femsyr.2005.02.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 02/16/2005] [Accepted: 02/17/2005] [Indexed: 11/29/2022] Open
Abstract
Trypsin is a highly valuable protease that has many industrial and biomedical applications. The growing demand for non-animal sources of the enzyme and for trypsins with special properties has driven the interest to clone and express this protease in microorganisms. Reports about expression of recombinant trypsins show wide differences in the degree of success and are contained mainly in patent applications, which disregard the difficulties associated with the developments. Although the yeast Pichia pastoris appears to be the microbial host with the greatest potential for the production of trypsin, it has shown problems when expressing cold-adapted fish trypsins (CAFTs). CAFTs are considered of immense value for their comparative advantage over other trypsins in a number of food-processing and biotechnological applications. Thus, to investigate potential obstacles related to the production of CAFTs in P. pastoris, the cunner fish trypsin (CFT) was cloned in different Pichia expression vectors. The vectors were constructed targeting both internal and secreted expression and keeping the CFT native signal peptide. Western-blotting analysis confirmed the expression with evident differences for each construct, observing a major effect of the leader peptide sequence on the expression patterns. Immobilized nickel affinity chromatography yielded a partially purified recombinant CFT, which exhibited trypsin-specific activity after activation with bovine enterokinase.
Collapse
Affiliation(s)
- Martin Macouzet
- Department of Food Science and Agricultural Chemistry, McGill University, Macdonald Campus, Ste-Anne-de-Bellevue, QC, Canada
| | | | | |
Collapse
|