Understanding the molecular mechanism of fumonisin esterases by kinetic and structural studies

• Published in: Food chemistry Vol. 473; p. 143110
• Main Authors: Incze, Dániel J., Molnár, Zsófia, Nagy, Gergely N., Leveles, Ibolya, Vértessy, Beáta G., Poppe, László, Bata, Zsófia
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2025
• Subjects: Acyl migration; arginine; Biocatalysis; Enzyme mechanism; esterases; Esterases - chemistry; Esterases - genetics; Esterases - metabolism; food chemistry; Fumonisin B1; Fumonisin esterase; fumonisins; Fumonisins - chemistry; Fumonisins - metabolism; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungal Proteins - metabolism; glutamic acid; Hydrolysis; Kinetics; Mycotoxin; Protein crystallography; regioselectivity; serine; Substrate Specificity; X-radiation; Acyl migration; Fumonisin B1; Enzyme mechanism; Fumonisin esterase; Protein crystallography; Mycotoxin; Hydrolyzed Fumonisin B1 (PubChem CID: 15875284); Fumonisin B1 (PubChem CID: 2733487); Fumonisin B1 esterase (SID: 405229404); Fumonisin B; Hydrolyzed Fumonisin B (PubChem CID: 15875284); Fumonisin B (PubChem CID: 2733487); Fumonisin B esterase (SID: 405229404)
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2025.143110

Fumonisins are sphingolipid-like mycotoxins that cause serious damage by contaminating food and feed. The tricarballylic acid (TCA) units of fumonisin B1 (FB1; accounting for 70 % of fumonisin contamination) can be removed by fumonisin B1 esterase (FE, EC 3.1.1.87) providing a biotechnological FB1 detoxification possibility. Here, we report the regioselective cleavage of the TCA ester at C6 in the first step of FB1 hydrolysis and kinetic characterization for two FEs. The low KM values (4.76–44.3 μM) are comparable to concentrations of environmental contaminations, and the high catalytic efficiencies are promising for practical applications. The X-ray structure of one of the FEs enabled the understanding of the FB1 hydrolysis at molecular level and revealed an arginine pocket key for substrate binding, and the catalytic role of the glutamate preceding the catalytic serine. Computations showed that this FE is likely capable of detoxifying any fumonisin indicating its potential applicability in food and feed products. •Hydrolytic degradation of Fumonisin B1 by two distinct fumonisin esterases is highly regioselective.•The intermediate is unambiguously assigned as the monoester at the C-7 position.•Enzyme kinetic parameters of the two fumonisin esterases with Fumonisin B1 and the C-7 monoester intermediate are determined.•A high-resolution X-ray structure of FE2 is determined.•In silico results suggest FE2 to be a general fumonisin esterase for fumonisins of series A, B, C, and P.