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Published on: October 16, 2015
In vitro study on the interaction between thiophanate methyl and human serum albumin
Jinhua Li1, Xiaoyan Liu, Cuiling Ren
1Department of Chemistry, Lanzhou University, No. 222 Tianshui Road, Lanzhou 730000, China.
Abstract:
Thiophanate methyl (MT) is one of the widely used fungicides to control important fungal diseases of crops, which has led to potential toxicological risk to public health. Several different transport proteins exist in blood plasma, but albumin only is bound by a wide diversity of xenobiotics reversibly with high affinity. We studied the interaction of MT with human serum albumin by using spectroscopic methods including fluorescence quenching technology, UV and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. The result of fluorescence titration revealed that MT could quench the intrinsic fluorescence of HSA. The binding process was exothermic and spontaneous, as indicated by the thermodynamic analyses. In addition, the studies of FT-IR spectroscopy showed that the binding of MT to HSA changed molecular conformation of HSA. The results obtained from molecular modeling showed that the interaction between MT and HSA was dominated by hydrophobic force, and there was also hydrogen bond interaction between the pesticide and the residues of HSA, which was in good agreement with the result of binding mode.
Insights
Thiophanate methyl (MT), a common fungicide, binds to human serum albumin (HSA). This interaction, driven by hydrophobic forces and hydrogen bonds, alters HSA
Area of Science:
- Biochemistry
- Toxicology
- Pharmacology
Background:
- Thiophanate methyl (MT) is a widely used fungicide, posing potential toxicological risks.
- Human serum albumin (HSA) is a primary transporter of xenobiotics in blood plasma.
- Understanding xenobiotic-protein interactions is crucial for assessing toxicological impact.
Purpose of the Study:
- To investigate the binding interaction between thiophanate methyl (MT) and human serum albumin (HSA).
- To elucidate the binding mechanism and thermodynamic properties of the MT-HSA complex.
- To determine the conformational changes in HSA upon binding with MT.
Main Methods:
- Spectroscopic techniques: Fluorescence quenching, UV-Vis absorption, and Fourier transform infrared (FT-IR) spectroscopy.
- Simulated physiological conditions for binding studies.
- Molecular modeling for predicting binding modes and forces.
Main Results:
- MT effectively quenched the intrinsic fluorescence of HSA, indicating binding.
- Thermodynamic analysis revealed a spontaneous and exothermic binding process.
- FT-IR spectroscopy demonstrated that MT binding induced conformational changes in HSA.
- Molecular modeling identified hydrophobic interactions and hydrogen bonds as dominant forces in MT-HSA binding.
Conclusions:
- Thiophanate methyl binds to human serum albumin through spontaneous, exothermic interactions.
- The binding involves hydrophobic forces and hydrogen bonds, leading to HSA conformational alterations.
- These findings provide insights into the toxicokinetics and toxicodynamics of thiophanate methyl.
