Insight into the binding behavior, structure, and thermal stability properties of β-lactoglobulin/Amoxicillin complex in a neutral environment

Antibiotics are extensively used in agriculture and husbandry, thus threatening human health due to their direct exposure to dairy products. Therefore, it is essential to investigate whether milk proteins are unintended carriers of antibiotics. In this research, therefore, we studied the impact of Amoxicillin on the conformation and structural stability of whey protein beta-lactoglobulin by using spectroscopic techniques combined with molecular docking and simulation approaches. Further, the thermal stability of the resultant complex was explored. Amoxicillin was observed to effectively quench beta-lactoglobulin's intrinsic fluorescence, suggesting that Amoxicillin was successfully bound to the beta-lactoglobulin and a stable complex between them was established. The thermodynamic parameters demonstrated that van der Waals forces and hydrogen bonds dominated the spontaneous bonding process. According to circular dichroism (CD) and Fourier transform infrared (FTIR) analyses, the conformational structure of the beta-lactoglobulin was altered upon the complexation with Amoxicillin. Further, this interaction significantly enhanced the thermal stability of beta-lactoglobulin compared to sole beta-lactoglobulin solutions. Molecular docking theoretically showed the preferred binding locus of Amoxicillin within the beta-lactoglobulin structure. Molecular dynamics (MD) simulation results further validated the stability of the beta-lactoglobulin-Amoxicillin complex. The findings obtained here are helpful for elucidating the potential of beta-lactoglobulin to bind and transport harmful substances into the body, thus opening up new avenues for food security.

Automated summary

This study investigated the impact of Amoxicillin on the conformation and structural stability of whey protein beta-lactoglobulin. The results showed that Amoxicillin effectively bound to beta-lactoglobulin, forming a stable complex. The binding process was dominated by van der Waals forces and hydrogen bonds. The complexation also altered the conformation and enhanced the thermal stability of beta-lactoglobulin. Molecular docking and simulation confirmed the stability of the complex. These findings provide insights into the potential of beta-lactoglobulin as a carrier for harmful substances, opening up new avenues for food security research.