One- and Two-Proton Transfer Mechanisms Coexist in One Active Site
| Autor: | Juan Gao, Jing Ren, Cheng-Shi Jiang, Jiali Song, Huaikun Dong, Jianzhuang Yao, Xia Wang, Yueqi Zhao |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
biology Esterases Salicylic acid binding Active site Esterase Combinatorial chemistry Surfaces Coatings and Films Catalysis Hydrolysis Enzyme chemistry Tetrahedral carbonyl addition compound Catalytic Domain Tobacco Materials Chemistry biology.protein Protons Physical and Theoretical Chemistry Systemic acquired resistance Plant Proteins |
| Zdroj: | The Journal of Physical Chemistry B. 124:6699-6708 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/acs.jpcb.0c04445 |
| Popis: | Acibenzolar-S-methyl (ASM) is one of the most successfully commercialized plant activators of the systemic acquired resistance (SAR). However, its activation (hydrolysis) mechanism catalyzed by the salicylic acid binding protein 2 (SABP2) remains elusive. The fundamental catalytic mechanism of the SABP2-catalyzed hydrolysis of the ASM had been investigated by extensive computational and experimental studies, including QM/MM simulations, charge transfer analysis, small-molecule synthesis, and biochemical assays. Here we report that the promiscuous SABP2 shows different catalytic mechanisms toward different substrates. To catalyze the ASM hydrolysis, the SABP2 uses a two-proton transfer mechanism, and the key intermediate is stabilized by the charge transfer effect; to catalyze the ethyl 1,2,3-benzothiadiazole-7-carboxylate (BTM, an ASM analogue) hydrolysis, the SABP2 applies the one-proton transfer mechanism, and the classic tetrahedral intermediate is stabilized by the electrostatic effect. The HPLC analyses of the SABP2 esterase activities toward the ASM and the BTM show comparable results with our computaional results, suggesting that the obtained computational mechanism insights are reasonable. The obtained mechanism is not only an important supplement to the theory of enzymes' catalytic promiscuity, but it also contributes a possible strategy for the design of next generation plant SAR activators. |
| Databáze: | OpenAIRE |
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