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A central feature of a variety of related neurological disorders, including amyotrophic lateral sclerosis (ALS), is the deposition of misfolded protein aggregates in key regions of the human brain. Hence, targeting aggregation-prone SOD1 with small molecules can be used to design strategies to inhibit its aggregation. Based on molecular docking and molecular dynamics (MD) simulation, this study suggested that plant flavonoids can act as a potent anti-amyloidogenic polyphenol against SOD1 aggregation. Initial screening of flavonoids against protein aggregates identified Rosmarinic acid and Salvianolic acid A as promising drug leads that can effectively inhibit pathogenic behaviour. Our results showed that Salvianolic acid A reduces the β-sheet content and increases the structural stability, hydrophobicity, flexibility, and significantly the lost hydrogen bonds of the mutant compared to other compounds. Besides, we revealed changes in the free energy landscape (FEL) of WT-SOD1 and mutant states (unbound/bound) to differentiate aggregation. We deduced that the above-mentioned flavonoids can deviation the pathogenic behaviour of the D124 V mutant. Among them, Salvianolic acid A showed the greatest therapeutic potential against the D124 V mutant. Hence, Salvianolic acid A could serve as a drug candidate for the design of highly efficient inhibitors in reducing fatal and irreversible ALS. [ABSTRACT FROM AUTHOR]

Disturbances in metal ion homeostasis associated with amyotrophic lateral sclerosis (ALS) have been described for several years, but the exact mechanism of involvement is not well understood. To elucidate the role of metalation in superoxide dismutase (SOD1) misfolding and aggregation, we comprehensively characterized the structural features (apo/holo forms) of WT-SOD1 and P66R mutant in loop IV. Using computational and experimental methodologies, we assessed the physicochemical properties of these variants and their correlation with protein aggregation at the molecular level. Modifications in apo-SOD1 compared to holo-SOD1 were more pronounced in flexibility, stability, hydrophobicity, and intramolecular interactions, as indicated by molecular dynamics simulations. The enzymatic activities of holo/apo-WT SOD1 were 1.30 and 1.88-fold of the holo/apo P66R mutant, respectively. Under amyloid-inducing conditions, decreased ANS fluorescence intensity in the apo-form relative to the holo-form suggested pre-fibrillar species and amyloid aggregate growth due to occluded hydrophobic pockets. FTIR spectroscopy revealed that apo-WT-SOD1 and apo-P66R exhibited a mixture of parallel and intermolecular β-sheet structures, indicative of aggregation propensity. Aggregate species were identified using TEM, Congo red staining, and ThT/ANS fluorescence spectroscopy. Thermodynamic analyses with GdnHCl demonstrated that metal deficit, mutation, and intramolecular disulfide bond reduction are essential for initiating SOD1 misfolding and aggregation. These disruptions destabilize the dimer-monomer equilibrium, promoting dimer dissociation into monomers and decreasing the thermodynamic stability of SOD1 variants, thus facilitating amyloid/amorphous aggregate formation. Our findings offer novel insights into protein aggregation mechanisms in disease pathology and highlight potential therapeutic strategies against toxic protein aggregation, including SOD1., (© 2024 Wiley Periodicals LLC.)

Background: One neurodegenerative disorder that is caused by a mutation in the hSOD1 gene is Amyotrophic lateral sclerosis (ALS)., Objectives: The current study was developed in order to evaluate the effect exerted by two ALS-associated point mutations, L67P and D76Y are located in the metal-binding loop, on structural characterization of hSOD1 protein using molecular dynamics (MD) simulations and computational predictions., Materials and Methods: In this study, GROMACS was utilized to perform molecular dynamics simulations along with 9 different algorithms such as Predict SNP, PhD-SNP, MAPP, PolyPhen-1, Polyphen-2, SNP, SIFT, SNP&GO, and PMUT for predicting and also evaluating the mutational effect on the structural and conformational characterization of hSOD1., Results: Our study was done by several programs predicting the destabilizing and harmful effect exerted by mutant hSOD1. The deleterious effect of L67P mutation was predicted by MAPP and PhD-SNP algorithms, and D76Y mutation was predicted by 9 algorithms. Comparative studies that were conducted on mutants and wild-type indicated the altar in flexibility and protein conformational stability influenced the metal-binding loop's conformation. The outcomes of the MD exhibited an increase and decrease of flexibility for D76Y and L67P mutants compared to the wild type, respectively. On the other hand, analysis of the gyration radius indicated lower and higher compactness for D76Y and L67P, respectively, suggesting that replacing amino acid at the metal-binding loop can alter the protein compactness compared with the protein the wild type., Conclusions: Overall, these findings provided insight into the effect of mutations on the hSOD1, which leads to neurodegeneration disorders in humans. The results show that the mutations of L67P and D76Y influence the stability of protein conformational and flexibility associated with ALS disease. Thus, results of such mutations are can be a prerequisite to achieve a thorough understanding of ALS pathogenicity., (Copyright: © 2021 The Author(s); Published by Iranian Journal of Biotechnology.)