Interaction of Conazole Pesticides Epoxiconazole and Prothioconazole with Human and Bovine Serum Albumin Studied Using Spectroscopic Methods and Molecular Modeling

Abstract

The interactions of epoxiconazole and prothioconazole with human serum albumin and bovine serum albumin were investigated using spectroscopic methods complemented with molecular modeling. Spectroscopic techniques showed the formation of pesticide/serum albumin complexes with the static type as the dominant mechanism. The association constants ranged from 3.80 × 104–6.45 × 105 L/mol depending on the pesticide molecule (epoxiconazole, prothioconazole) and albumin type (human or bovine serum albumin). The calculated thermodynamic parameters revealed that the binding of pesticides into serum albumin macromolecules mainly depended on hydrogen bonds and van der Waals interactions. Synchronous fluorescence spectroscopy and the competitive experiments method showed that pesticides bind to subdomain IIA, near tryptophan; in the case of bovine serum albumin also on the macromolecule surface. Concerning prothioconazole, we observed the existence of an additional binding site at the junction of domains I and III of serum albumin macromolecules. These observations were corroborated well by molecular modeling predictions. The conformation changes in secondary structure were characterized by circular dichroism, three-dimensional fluorescence, and UV/VIS absorption methods.

Assessment of the Binding of Pseudallecin A to Human Serum Albumin with Multi‐Spectroscopic Analysis, Molecular Docking and Molecular Dynamic Simulation

“…3D fluorescence spectrometry is a valuable technology which can provide overall fluorescence information of samples and make the study of protein conformation changes more accurate and reliable. [37] 3D fluorescence spectra and their corresponding contour graph of HSA with and without PA were displayed in Figure 4. Peak 1 was the strongest peak at λ ex = 280 nm and λ em = 340 nm, which is related to the characteristic spectra of Trp and Tyr residues.…”

Novel Method for Extracting the Spectrum of a Supramolecular Complex via a Comprehensive Approach Involving Two-Dimensional Correlation Spectroscopy, Genetic Algorithm, and Grid Searching

“…Intermolecular interactions play a crucial role in many physical, chemical, and biological processes. − Various approaches, such as single-crystal X-ray diffraction, NMR spectroscopy, and microscale thermophoresis, have been adopted to characterize intermolecular interactions during the past several decades. − Molecular spectroscopic methods have attracted extensive attention. − Nevertheless, spectral variations caused by intermolecular interactions are often quite nuanced and are easily buried in complex molecular spectroscopic profiles in Fourier transform infrared (FTIR), Raman, UV–visible, and near-infrared (NIR) spectra.…”

Probing the potential toxicity by characterizing the binding mechanism of sodium dehydroacetate to human serum albumin

“…HSA can maintain normal blood osmotic pressure and pH value, combine and transport many endogenous and exogenous compounds in the blood. Hence, HSA is an important transport carrier protein 20 . After oral intake, DHA‐S can be rapidly absorbed by humans and animals, be distributed in the blood and multiple organs, and combined with serum proteins in the plasma 21 .…”

“…Hence, HSA is an important transport carrier protein. 20 After oral intake, DHA-S can be rapidly absorbed by humans and animals, be distributed in the blood and multiple organs, and combined with serum proteins in the plasma. 21 Once combined with HSA, DHA-S is very likely to affect the structure of HSA and even cause disorder to its function.…”