Interaction behavior between glycated human serum albumin and metformin in the presence of silver nanoparticles: a combination study of spectroscopic, calorimetric and molecular dynamic

In diabetes, human serum albumin (HSA) is an example of non-enzymatic glycation of proteins produced by hyperglycemia. According to common knowledge, glycation-associated modifications can cause an impact on HSA and consequently affect its binding with metformin (Met). This paper investigated the interaction between glycated HSA (gHSA) and metformin in the appearance and lack of Ag nanoparticles (AgNPs) at three different sizes by the means of multi-spectroscopic, calorimetric and molecular dynamic (MD) procedures. The binding and quenching features of metformin to gHSA throughout the absence and presence of AgNPs were assessed at various sizes by the exertion of fluorescence measurements. In conformity to synchronous and three-dimensional fluorescence spectra, the binding of metformin to gHSA within the presence of AgNPs caused conformational alternations in the surrounding of Trp and Tyr residues micro-environment. Moreover, a shift was recorded in the maximum wavelength toward the shorter wavelengths (blue shift). Considering the outcomes of resonance light scattering studies, a novel type of species with a larger size was formed by the gHSA-metformin complex, while its favorite interaction was gHSA-metformin complex in the presence of AgNPs. The FRET data confirmed the interaction between gHSA and Met throughout the absence and appearance of AgNPs. According to the quantitative analysis of far-UV CD spectra, the secondary construction of gHSA was altered by the enhancement of metformin in different concentrations which affirmed the improvement of electrostatic forces in the presence of AgNPs. Therefore, similar to the case of applied CD to the ternary system, the binding of metformin to gHSA determines structural changes that were observed to lack comparability in different sizes of AgNPs. The interaction heat behavior and stability of HSA and gHSA upon interaction with Met in the presence of AgNPs was revealed by calorimetric results. In conformity to the docking studies, the stability of protein backbone faced a notable increase in the presence of AgNPs along with the occurrence of changes in the secondary structure.

Automated summary

This study investigated the interaction between glycated HSA and Met, and observed the impact of AgNPs on the interaction. The results showed that the presence of AgNPs caused conformational changes in the binding of Met to gHSA, leading to the formation of a larger species. The stability and heat behavior of HSA and gHSA were also affected by the presence of AgNPs.