β-Carotene alleviates substrate inhibition caused by asymmetric cooperativity
Enzymes are essential catalysts in biological systems. Substrate inhibition, once dismissed, is now observed in 20% of enzymes<sup>1</sup> and is attributed to the formation of an unproductive enzyme-substrate complex, with no structural evidence of unproductivity provided to date<sup>1-6</sup>. This study uncovers the molecular mechanism of substrate inhibition in tobacco glucosyltransferase NbUGT72AY1, which transfers glucose to phenols for plant protection. The peculiarity that β-carotene strongly attenuates the substrate inhibition of NbUGT72AY1, despite being a competitive inhibitor, allows to determine the conformational changes that occur during substrate binding in both active and substrate-inhibited complexes. Crystallography reveals structurally different ternary enzyme-substrate complexes that do not conform to classical mechanisms. An alternative pathway suggests substrates bind randomly, but the reaction occurs only if a specific order is followed (asymmetric cooperativity). This unreported paradigm explains substrate inhibition and reactivation by competitive inhibitors, opening new research avenues in metabolic regulation and industrial applications.
Authors
- Umar F. Shahul Hameed (ORCID: https://orcid.org/0000-0002-0552-7149)
- Alessandro Nicoli (ORCID: https://orcid.org/0000-0001-6177-9749)
- Christina Kuttler (ORCID: https://orcid.org/0000-0002-5521-4159)
- Guangxin Sun (ORCID: https://orcid.org/0000-0001-6036-8809)
- Farhah F. Assaad (ORCID: https://orcid.org/0000-0002-8683-9039)
- Timothy D. Hoffmann (ORCID: https://orcid.org/0000-0001-8505-7126)
- Dragana A. M. Catici (ORCID: https://orcid.org/0000-0003-0494-9152)
- Thomas Hoffmann (ORCID: https://orcid.org/0009-0002-9366-9733)
- Stefan T. Arold (ORCID: https://orcid.org/0000-0001-5278-0668)
- Chuankui Song (ORCID: https://orcid.org/0000-0002-7852-1194)
- Wilfried G. Schwab (ORCID: https://orcid.org/0000-0002-9753-3967)
- Antonella Di Pizio (ORCID: https://orcid.org/0000-0002-8520-5165)
- Elisabeth Kurze (ORCID: https://orcid.org/0000-0001-8625-0737)
- Wieland Steinchen (ORCID: https://orcid.org/0000-0003-2990-3660)
- Jieren Liao
Institutions
- Anhui Agricultural University (CN)
- Philipps University of Marburg (DE)
- Loewe Center for Synthetic Microbiology (DE)
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich (DE)
- Technical University of Munich (DE)
- Massachusetts Institute of Technology (US)
- King Abdullah University of Science and Technology (SA)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-03-29
- DOI
- https://doi.org/10.1038/s41467-025-58259-7
- Citations
- 6
- Primary Topic
- Neurobiology and Insect Physiology Research
- Type
- article
- Field-Weighted Citation Impact
- 5.45
Funders
- Deutsche Forschungsgemeinschaft
- King Abdullah University of Science and Technology