Detailed investigation of effects of Zn 2+ , Fe 2+ and Cu 2+ metal ions on the binding interaction between eletriptan hydrochloride an anti-migraine headache drug and bovine serum albumin by various spectrometric techniques and molecular docking studies

In vitro investigation of the binding characteristics of dacomitinib to human α 1-acid glycoprotein: Multispectral and computational modeling

Dacomitinib is a highly selective second-generation tyrosine kinase inhibitor that can irreversibly bind to tyrosine kinase and is mainly used in the treatment of lung cancer. The binding characteristics of dacomitinib with human α 1-acid glycoprotein (HAG) were analyzed by multispectral and computational simulation techniques. The fluorescence spectra showed that dacomitinib can quench the fluorescence of HAG by forming the HAG-dacomitinib complex with a molar ratio of 1:1 (static quenching). At the temperature similar to that of the human body, the affinity of dacomitinib to HAG (8.95 × 106 M-1) was much greater than that to BSA (3.39 × 104 M-1), indicating that dacomitinib will give priority to binding onto HAG. Thermodynamics parameters analysis and driving force competition experiments showed that hydrogen bonding and hydrophobic forces were the major sources for keeping the complex of HAG-dacomitinib stable. The experimental outcomes also showed that the binding of dacomitinib can lead to the loosening of the skeleton structure of HAG, which led to a slight change in the secondary structure, and also reduces the hydrophobicity of the microenvironment of Trp and Tyr residues. The binding sites of dacomitinib on HAG and the contribution of key amino acid residues to the binding reaction were determined by molecular docking and molecular dynamics (MD) simulation. In addition, it was found that there was a synergistic effect between dacomitinib and Mg2+ and Co2+ ions. Mg2+ and Co2+ could increase the Kb of dacomitinib to HAG and prolong the half-life of dacomitinib.

Application of a Novel "Turn-on" Fluorescent Material to the Detection of Aluminum Ion in Blood Serum

A novel "turn-on" fluorescent bioprobe, 1,2,3,4,5-penta(4-carboxyphenyl)pyrrole sodium salt (PPPNa), with aggregation-enhanced emission characteristics was synthesized for the in situ quantitative detection of Al³⁺ in serum. It exhibited a high selectivity to Al³⁺ in both simulated serum and fetal calf serum with no interferences from other metal ions or serum components observed and no isolation required. A weak interaction between PPPNa and serum albumin was found, which caused no interference, but enhanced fluorescence response of PPPNa to Al³⁺ and improved detection sensitivity. The limit of detection was determined to be 1.50 μmol/L Al³⁺ in phosphate-buffered saline solution containing 33 μg/mL bovine serum albumin (BSA) and decreased to 0.98 μmol/L as BSA concentration increased to 100 μg/mL. The fluorescence "turn-on" mechanism of the PPPNa probe to detect Al³⁺ was proposed. A bidentate complex is formed between the carboxy group of PPPNa and Al³⁺, causing the photoluminescence (PL) emission enhancement by aggregation. BSA chains further strengthen the stacking compactness of the aggregates of PPPNa and Al³⁺ and consequently enhance the PL emission of PPPNa by further promoting the restriction of intramolecular rotation of the phenyl ring. Its application to the in situ Al³⁺ was successfully demonstrated with HeLa cells and NIH 3T3 cells. The low cytotoxicity and highly selective response of PPPNa to Al³⁺ endow its great potentials to in vivo detecting and imaging of Al³⁺ as well as an absorbent of Al³⁺.

Characterization of interaction between scoparone and bovine serum albumin: spectroscopic and molecular docking methods

Scoparone is a major biological active substance derived from the traditional Chinese herbal medicine called Artemisia capillaris. It has been confirmed that scoparone has anti-inflammatory, anti-tumor, hepatoprotective and antioxidant effects. However, the binding interaction of scoparone with bovine serum albumin (BSA) still remains unknown. Therefore, the present study was conducted to clarify the binding interaction of scoparone with BSA under simulated physiological conditions (pH = 7.4) by utilizing spectroscopic and molecular docking methods. The formation of the scoparone–BSA complex was identified by UV-vis absorption spectroscopy experiment results. The fluorescence experiment results revealed that the quenching mechanism was static quenching and the binding procedure was spontaneous mainly driven by hydrophobic interaction. At 310 K, the number of binding sites was approximately equal to 1 and the binding constant was 6.79 × 10⁵ mol L⁻¹. The binding distance (4.81 nm) between scoparone and BSA was determined by Förster's non-radiative energy transfer theory. Molecular docking and site marker competitive experiment results verified that scoparone was more likely to be located in site I of BSA. In addition, the results of synchronous fluorescence spectroscopy and circular dichroism spectroscopy experiments proved that scoparone slightly changed the conformation of BSA by binding interaction with BSA. These findings would be useful for understanding the pharmacokinetics of scoparone in vivo, including scoparone transport, distribution, metabolism and excretion.

The interaction of scoparone with bovine serum albumin (BSA) was studied by utilizing spectroscopic and molecular docking methodologies.