Interactions between Human Serum Albumin and Sulfadimethoxine Determined Using Spectroscopy and Molecular Docking.

Yuai Zhang,Xuemei Zhang,Yiqing Cao,Yan Li

doi:10.3390/molecules27051526

Yuai Zhang, Xuemei Zhang + Show 2 more

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https://doi.org/10.3390/molecules27051526

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Abstract

Sulfonamides are widely used antibiotics in agricultural production. However, the potential threat of these drugs to human health has increased global concern. Human serum albumin (HSA) is the main reservoir and transporter of exogenous small molecules in humans. In this study, the interaction between sulfadimethoxine (SMT) and human serum albumin (HSA) was studied using spectroscopy and computer simulation. Our results showed that the hydrogen bonding and van der Waals forces drove SMT to enter the binding site I of HSA spontaneously and resulted in the fluorescence quenching of HSA. The stability of the HSA–SMT complex decreased with an increase in temperature. The binding of SMT to HSA induced alterations in the secondary structure of HSA, where the content of α-helix decreased from 61.0% of the free state to 59.0% of the compound state. The π–π, π–σ, and π–alkyl interactions between HSA and SMT were found to play important roles in maintaining the stability of the complex.

Highlights

As one of the most widely used groups of antimicrobials, sulfonamides, including sulfadimethoxine (SMT), play a pivotal role in agriculture [1]
SMT was added to Human serum albumin (HSA) solution, the fluorescence intensity of HSA was quenched, and its position exhibited a blue shift toward 338 nm
Fluorescence quenching of HSA by SMT was performed at 298 K, 303 K, and 308 K, and the corresponding binding constants were 2.31 × 10−4 L·mol−1, 1.25 × 10−4 L·mol−1, and 0.83 × 10−4 L·mol−1, respectively. These results indicated that the stability of HSA–SMT was inversely regulated by temperature, which in turn supported the conclusion that SMT led to the static quenching of HSA [28]

Summary

Introduction

As one of the most widely used groups of antimicrobials, sulfonamides, including sulfadimethoxine (SMT), play a pivotal role in agriculture [1]. Recent studies have shown that sulfonamides, together with their metabolites, may pose a potential threat to human health by virtue of their accumulation in the body through the food chain [2]. The permissible limits of sulfonamides in food (e.g., bread, eggs, and milk) and feed established by the EU, US-FDA, and China are. Sulfonamides are a growing cause of health concern because of its high levels in edible agricultural and food products [5,6]. There is an urgent need to determine the mechanism of toxicity of sulfonamides on human health

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