Interaction study of engeletin toward cytochrome P450 3A4 and 2D6 by multi-spectroscopy and molecular docking

Study on the binding of polystyrene microplastics with superoxide dismutase at the molecular level by multi-spectroscopy methods

Microplastics are harmful pollutants that widely exist worldwide and pose a severe threat to all types of organisms. The effects of polystyrene microplastics (PS-MPs) on organisms have been extensively studied, but the interaction mechanism between PS-MPs and superoxide dismutase (SOD) at the molecular level has not been reported yet. Therefore, based on multiple spectroscopic methods and enzyme activity measurements, the molecular mechanism of the interaction between PS-MPs and SOD was investigated. The multispectral results showed that the protein skeleton and secondary structure of SOD were altered by PS-MPs, resulting in decreased α-helix and β-sheet content. After PS-MPs exposure, fluorescence sensitization occurred, and micelles were formed, along with the enhanced hydrophobicity of aromatic amino acids in SOD. Moreover, the resonance light scattering (RLS) spectra result suggested that the PS-MPs and SOD combined to form a larger complex. Eventually, the activity of SOD was increased due to these structural changes, and the concentration of PS-MPs is positively correlated with SOD activity. This study can provide experimental support for studying the toxicological effects of PS-MPs.

Phylogenetic Analysis and Protein Modelling of Isoflavonoid Synthase Highlights Key Catalytic Sites towards Realising New Bioengineering Endeavours

Isoflavonoid synthase (IFS) is a critical enzyme for the biosynthesis of over 2400 isoflavonoids. Isoflavonoids are an important class of plant secondary metabolites that have a range of pharmaceutical and nutraceutical properties. With growing interest in isoflavonoids from both research and industrial perspectives, efforts are being forwarded to enhance isoflavonoid production in-planta and ex-planta; therefore, in-silico analysis and characterisation of available IFS protein sequences are needed. The present study is the first-ever attempt toward phylogenetic analysis and protein modelling of available IFS protein sequences. Phylogenetic analysis has shown that IFS amino acid sequences have 86.4% pairwise identity and 26.5% identical sites, and the sequences were grouped into six different clades. The presence of a β-hairpin and extra loop at catalytic sites of Trifolium pratense, Beta vulgaris and Medicago truncatula, respectively, compared with Glycyrrhiza echinata are critical structural differences that may affect catalytic function. Protein docking highlighted the preference of selected IFS for liquiritigenin compared with naringenin and has listed T. pratense as the most efficient candidate for heterologous biosynthesis of isoflavonoids. The in-silico characterisation of IFS represented in this study is vital in realising the new bioengineering endeavours and will help in the characterisation and selection of IFS candidate enzymes for heterologous biosynthesis of isoflavonoids.

Interaction mechanism of pelargonidin against tyrosinase by multi-spectroscopy and molecular docking

The interaction mechanism of pelargonidin (PG) with tyrosinase was investigated by multi-spectroscopy and molecular docking. As a result, PG had strong inhibitory activity on tyrosinase with the IC₅₀ value of 41.94×10^-6 mol·L^-1 . The inhibition type of PG against tyrosinase was determined as a mixed mode. Meanwhile, the fluorescence of tyrosinase was quenched statically by PG, and accompanied by non-radiative energy transfer. The three-dimensional (3-D) fluorescence, ultraviolet-visible spectroscopy (UV-Vis) and circular dichroism spectroscopies (CD) indicated that PG decreased the hydrophobicity of the micro-environment around tryptophan (Trp) and tyrosine (Tyr), which resulted in the conformational change of tyrosinase. In addition, fluorescence and molecular docking analysis indicated that PG bound to tyrosinase via hydrogen bonds (H-bonds) and van der Waals force (vdW force). We herein recommended that PG might be a potential candidate drug for the treatment of melanin-related diseases.