A comparative analysis on the binding characteristics of various mammalian albumins towards a multitherapeutic agent, pinostrobin

Interaction of Cephalosporins with Human Serum Albumin: A Structural Study

Modification of the R1 and R2 side chain structures has been used as the main strategy to expand the spectrum of cephalosporins and impart resistance to hydrolysis by β-lactamases. These structural modifications also result in a wide range of plasma protein binding, especially with human serum albumin (HSA). Here, we determined the crystal structures of the HSA complexes with two clinically important cephalosporins, ceftriaxone and cefazolin, and evaluated the binding of cephalosporin to HSA by susceptibility testing and competitive binding assay. Ceftriaxone and cefazolin bind to subdomain IB of HSA, and their cephem core structures are recognized by Arg117 of HSA. Tyr161 of HSA changes its rotamer depending on the cephalosporin, resulting in alterations of the cavity shape occupied by the R2 side chain of cephalosporins. These findings provide structural insight into the mechanisms underlying the HSA binding of cephalosporins.

Molecularly Imprinted Nanogels Capable of Porcine Serum Albumin Detection in Raw Meat Extract for Halal Food Control

Accurate, simple, and valuable analytical methods for detection of food contamination are rapidly expanding to evaluate the validity of food product quality because of ethnic considerations and food safety. Herein molecularly imprinted nanogels (MIP-NGs), capable of porcine serum albumin (PSA) recognition, were prepared as artificial molecular recognition elements. The MIP-NGs were immobilized on a quartz crystal microbalance (QCM) sensor for detection of pork contamination in real beef extract samples. The MIP-NGs-based QCM sensor showed high affinity and excellent selectivity toward PSA compared to reference serum albumins from five different animals. The high PSA specificity of MIP-NGs led to the detection of pork contamination with a detection limit of 1% (v/v) in real beef extract samples. We believe the artificial molecular recognition materials prepared by molecular imprinting are a promising candidate for halal food control.

A critical view on the analysis of fluorescence quenching data for determining ligand-protein binding affinity

The past decade has seen an increase in the number of research papers on ligand binding to proteins based on fluorescence spectroscopy. In most cases, determination of the binding affinity is made by analyzing the quenching of protein fluorescence induced by the ligand. However, many such articles, even those published in reputed journals, suffer from several mistakes with regard to analysis of fluorescence quenching data. Using the binding of phenylbutazone to human serum albumin as a model, we consider some of these mistakes and show how they affect the values of the association constant. In particular, the failure to correct for the inner filter effect and the use of unsuitable equations are discussed. Ligand binding data presented in these articles should be treated with caution, especially in the absence of data from complementary techniques.

Comparison of pendimethalin binding properties of serum albumins from various mammalian species

Background

To investigate the interaction of pendimethalin (PM), a commonly used herbicide, with various mammalian serum albumins.

Methods

The interactions of PM with serum albumins of bovine (BSA), sheep (SSA), porcine (PSA) and rabbit (RbSA) were studied using fluorescence quenching titration and site marker displacement experiments.

Results

A comparison of the PM-induced quenching of the fluorescence of these albumins with that published for human serum albumin (HSA) showed similarity between BSA and HSA. The PM binding affinity of these albumins was found to follow the order: SSA>BSA>RbSA>PSA. Warfarin (WFN) displacement results also suggested similar displacing action of PM on WFN-BSA complex, when compared to the published results on WFN-HSA complex.

Conclusion

The results suggested close similarity between BSA and HSA in terms of PM binding characteristics and hence bovine can be selected as a suitable animal model for further toxicological studies of PM.

Biomolecular interactions of amphotericin B nanomicelles with serum albumins: A combined biophysical and molecular docking approach

In this work, we investigated the interaction of amphotericin B (AmB) nanomicelles on the binding affinity and conformational change of human serum albumin (HSA) in comparison with bovine serum albumin (BSA) under physiological conditions by conducting several spectroscopic techniques further confirmed through molecular docking approaches. The experimental results showed that AmB nanomicelles could bind to both HSA and BSA to form protein/drug complexes with one binding site, and the binding process was spontaneous under physiological conditions. Fluorescence studies revealed that the quenching mechanism of these complexes was static quenching rather than dynamic quenching and exhibited strong binding between serum albumin and AmB nanomicelles. The results from UV-Visible spectra, FT-IR spectra, and CD spectra revealed that the AmB formulations affected the structure of both HSA and BSA proteins by changing the microenvironment around the tryptophan residues of protein and caused a secondary structure change of the protein with the loss of helical stability. The molecular docking experiments also supported the above results and effectively proved the binding and changes in the conformation of serum albumins by AmB micelles. This finding provides information of in vitro drug-plasma protein interactions for further study on the AmB binding mechanism and the pharmacodynamics and pharmacokinetics.

Species Differences in the Binding of Sodium 4-Phenylbutyrate to Serum Albumin

Sodium 4-phenylbutyrate (PB) is clinically used as a drug for treating urea cycle disorders. Recent research has shown that PB also has other pharmacologic activities, suggesting that it has the potential for use as a drug for treating other disorders. In the process of drug development, preclinical testing using experimental animals is necessary to verify the efficacy and safety of PB. Although the binding of PB to human albumin has been studied, our knowledge of its binding to albumin from the other animal species is extremely limited. To address this issue, we characterized the binding of PB to albumin from several species (human, bovine, rabbit, and rat). The results indicated that PB interacts with 1 high-affinity site of albumin from these species, which corresponds to site II of human albumin. The affinities of PB to human and bovine albumins were higher than those to rabbit and rat albumin, and that to rabbit albumin was the lowest. Binding and molecular docking studies using structurally related compounds of PB suggested that species differences in the affinity are attributed to differences in the structural feature of the PB-binding sites on albumins (e.g., charge distribution, hydrophobicity, shape, or size).