Experimental and computational characterization on the binding of two fluoroquinolones to bovine hemoglobin

Abstract

Ciprofloxacin (CPFX) and enrofloxacin (ENFX) are 2 representatives of widely used fluoroquinolones (FQs) with many human and veterinary applications. The residues of FQs in the environment are potentially harmful. Recently, great concern has been paid to their persistence and fate in the environment because of the potential adverse effects on humans and ecosystem functions. In the present study, we examined the interactions of bovine hemoglobin (BHb) with these 2 FQs by means of multiple spectroscopic and molecular docking methods under physiological conditions. The experimental results revealed that both FQs could bind with BHb to form complexes mainly through electrostatic interactions. And CPFX posed more of an affinity threat to BHb than ENFX. On the basis of molecular docking, both FQs could bind into the central cavity of BHb and interact with the residue Trp 37, resulting in the remarkable fluorescence quenching of protein. Additionally, as shown by the synchronous fluorescence, UV-visible absorption and circular dichroism data, both CPFX and ENFX could lead to the conformational and microenvironmental changes of BHb, which may affect its physiological functions. The work is beneficial for understanding the biological toxicity of FQs in vivo.

Spectroscopic characterization, calorimetric study and molecular docking to evaluate the bioconjugation of maltol with hemoglobin

“…As shown in Figure , the fluorescence intensity of these two residues decreased and red‐shifted gradually, indicating the conformational changes of Trp and Try (the polarity is increased and the hydrophobicity is decreased) . Similar phenomenon was observed in Qin et al’s study confirming that conformational and microenvironmental changes occur in BHb in the presence of maltol …”

Esterase activity and conformational changes of bovine serum albumin toward interaction with mephedrone: Spectroscopic and computational studies

“…Fluorescence spectroscopy was utilized to probe the structure and dynamics of biomacromolecules and their binding with small compound. Fluorescence quenching is described as the decrease in the fluorescence intensity due to the environmental alteration around the fluorophore, which can expose the nature of binding reaction . The 3 intrinsic fluorophores present in BSA are phenylalanine, tyrosine, and tryptophan residue.…”

Nitrogen and sulfur co‐doped carbon nanodots toward bovine hemoglobin: A fluorescence quenching mechanism investigation

“…It consists of a protein portion (globin) and 4 iron‐containing parts, and it is responsible for oxygen‐carbon dioxide carrying in the vascular system of humans and animals. It can also aid in the balance of the blood pH and can remove hydrogen ions in the capillaries and carry them to the lungs . Because of the crucial biochemical importance of Hb in mammal animals, several new analytical methods, such as fluorometric, electrochemical, colorimetric, and chemiluminescence methods, have been reported for its determination and quantification .…”