Molecular recognition of malachite green by hemoglobin and their specific interactions: insights from in silico docking and molecular spectroscopy

Abstract

Malachite green is an organic compound that can be widely used as a dyestuff for various materials; it has also emerged as a controversial agent in aquaculture. Since malachite green is proven to be carcinogenic and mutagenic, it may become a hazard to public health. For this reason, it is urgently required to analyze this controversial dye in more detail. In our current research, the interaction between malachite green and hemoglobin under physiological conditions was investigated by the methods of molecular modeling, fluorescence spectroscopy, circular dichroism (CD) as well as hydrophobic ANS displacement experiments. From the molecular docking, the central cavity of hemoglobin was assigned to possess high-affinity for malachite green, this result was corroborated by time-resolved fluorescence and hydrophobic ANS probe results. The recognition mechanism was found to be of static type, or rather the hemoglobin-malachite green complex formation occurred via noncovalent interactions such as π-π interactions, hydrogen bonds and hydrophobic interactions with an association constant of 10(4) M(-1). Moreover, the results also show that the spatial structure of the biopolymer was changed in the presence of malachite green with a decrease of the α-helix and increase of the β-sheet, turn and random coil suggesting protein damage, as derived from far-UV CD and three-dimensional fluorescence. Results of this work will help to further comprehend the molecular recognition of malachite green by the receptor protein and the possible toxicological profiles of other compounds, which are the metabolites and ramifications of malachite green.

Size Dependent Uptake and Hemolytic Effect of Zinc Oxide Nanoparticles on Erythrocytes and Biomedical Potential of ZnO-Ferulic acid Conjugates

“…Where the intensity of peak is increasing compared to free Hb while decreasing the size of ZnONPs, it indicates the secondary structural changes of protein. It is clear that lower size (<50 nm) have high impact on change in helixcity and some degree of unfolding on Hb 52 . While increasing the size (50–100 and >100 nm) the impact of unfolding is very less.…”

Binding of fluorescent acridine dyes acridine orange and 9-aminoacridine to hemoglobin: Elucidation of their molecular recognition by spectroscopy, calorimetry and molecular modeling techniques

“…The fluorescence dye ANS is a versatile hydrophobic probe that may give information about the hydrophobic domain on the protein surfaces and is very sensitive to their microenvironment [54]. Many studies have used ANS displacement assay recently to probe the binding of ligands to HHb [28,29,31]. ANS binds to the hydrophobic region of the central cavity of HHb.…”

“…This may lead to exposure of HHb to drugs and small molecules present in the plasma leading to interaction. A few reports on ligand-hemoglobin interactions have been published recently [27][28][29][30][31][32][33]. The molecular aspects of the recognition between acridine dyes and HHb and the related thermodynamics are not yet investigated.…”

Quest for the binding mode of malachite green with humic acid

“…6, which revealed that MG molecule approached towards the gaps of HA bearing aromatic rings. These results also implied that there were p-p stacking interactions of MG with HA [34]. From the modelling studies, we did not find Hbond in the binding system.…”