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The molecular basis of protein unfolding on exposure to the widely used herbicide, Glyphosate (GLY), its metabolite aminomethylphosphonic acid (AMPA), and the commercial formulation Roundup have been probed using human and bovine serum albumins (HSA and BSA). Protein solutions were exposed to chemical stress at set experimental conditions. The study proceeds with spectroscopic and imaging tools. Steady-state and time-resolved fluorescence (TRF) measurements indicated polarity changes with the possibility of forming a ground-state complex. Atomic force microscopy imaging results revealed the formation of fibrils from BSA and dimer, trimer, and tetramer forms of oligomers from HSA under the chemical stress of GLY. In the presence of AMPA, serum albumins (SAs) form a compact network of oligomers. The compact network of oligomers was transformed into fibrils for HSA with increasing concentrations of AMPA. In contrast, Roundup triggered the formation of amorphous aggregates from SAs. Analysis of the Raman amide I band of all aggregates showed a significant increase in antiparallel β-sheet fractions at the expense of α-helix. The highest percentage, 24.6%, of antiparallel β-sheet fractions was present in amorphous aggregate formed from HSA under the influence of Roundup. These results demonstrated protein unfolding, which led to the formation of oligomers and fibrils., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The successful evolution of an effective drug depends on its pharmacokinetics, efficiency and safety and these in turn depend on the drug-target/drug-carrier protein binding. This work, deals with the interaction of a pyridine derivative, 2-hydroxy-5-(4-methoxyphenyl)-6-phenylpyridine 3-carbonitrile (HDN) with serum albumins at physiological conditions utilizing the steady state and time-resolved fluorescence techniques by probing the emission behavior of Trp in BSA and HSA. In-silico studies revealed a combined static and dynamic quenching mechanism for the interactions. The binding studies suggests a spontaneous binding between HDN and the albumins with a moderate binding affinity (Kb ∼ 10 -5  M-1) with a single class of binding site. The FRET mediated emission from HDN indicates preferential binding of HDN in subdomain IIA of the albumins with Trp residue in close proximity. Circular dichroism results indicate HDN induced conformational changes for BSA and HSA, but the α-helical secondary structure was well preserved even up to a concentration of 10 µM HDN. Moderate binding affinity of HDN with BSA and HSA and the unaltered secondary structure of proteins on binding propose the potential application of HDN as an efficient drug. The application of docking method on the affinity of HDN towards the proposed target/receptor is discussed., (Copyright © 2022. Published by Elsevier B.V.)

The interaction of bisphenol-S (BPS) with serum albumins using steady-state, synchronous, time-resolved, and circular dichroism spectroscopies has been investigated. The binding interactions have also been investigated in the case of bisphenol A (BPA). The fluorescence quenching pathways are different for both of these endocrine disrupting compounds. Steady-state and time-resolved studies reveal static quenching at lower concentrations of BPS and dynamic quenching at higher concentrations. CD results also maintained the concentration dependent variation with a complete distortion of α-helices at 10(-5) M BPS. Besides this, addition of sodium dodecyl sulfate (SDS) results in the further unfolding of protein in the case of BPS, whereas time-resolved studies indicated refolding for BPA denatured human serum albumin (HSA). The entire study indicates an irreversible binding of BPS with HSA. Hence, these results reveal the possible involvement of BPS in the physiological pathway raising a health threat as already their presences in body fluids are known.