Robertson, A.J., Wilson, A.L., Burn, M.J. et al. (3 more authors) (2021) The relationship between enzyme conformational change, proton transfer, and phosphoryl transfer in β-phosphoglucomutase. ACS Catalysis, 2021 (11). pp. 12840-12849. ISSN 2155-5435
Abstract
Molecular details for the timing and role of proton transfer in phosphoryl transfer reactions are poorly understood. Here, we have combined QM models, experimental NMR measurements, and X-ray structures to establish that the transition of an archetypal phosphoryl transfer enzyme, βPGM, from a very closed near-attack conformation to a fully closed transition state analogue (TSA) conformation triggers both partial proton transfer from the general acid–base residue to the leaving group oxygen and partial dissociation of the transferring phosphoryl group from the leaving group oxygen. Proton transfer continues but is not completed throughout the reaction path of the phosphoryl transfer with the enzyme in the TSA conformation. Moreover, using interacting quantum atoms (IQA) and relative energy gradient (REG) analysis approaches, we observed that the change in the position of the proton and the corresponding increased electrostatic repulsion between the proton and the phosphorus atom provide a stimulus for phosphoryl transfer in tandem with a reduction in the negative charge density on the leaving group oxygen atom. The agreement between solution-phase 19F NMR measurements and equivalent QM models of βPGMWT and βPGMD10N TSA complexes confirms the protonation state of G6P in the two variants, validating the employed QM models. Furthermore, QM model predictions of an AlF4 distortion in response to the proton position are confirmed using high resolution X-ray crystal structures, not only providing additional validation to the QM models but also further establishing metal fluorides as highly sensitive experimental predictors of active-site charge density distributions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Authors. Article available under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/4.0). |
Keywords: | enzyme catalysis; phosphoryl transfer; proton transfer; transition state analogue; relative energy gradient |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Biosciences (Sheffield) |
Funding Information: | Funder Grant number Biotechnology and Biological Sciences Research Council BB/E017541/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 04 Nov 2021 08:14 |
Last Modified: | 11 Feb 2023 02:37 |
Status: | Published |
Publisher: | American Chemical Society (ACS) |
Refereed: | Yes |
Identification Number: | 10.1021/acscatal.1c01389 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:180002 |