Molecular insights into the crystalline nanocellulose and human lysozyme interactions: An experimental and theoretical research

In the present research, we performed a combination of detailed computational and spectroscopic methods to determine the effect of crystalline nanocellulose (CNC) on the structure and dynamics of human lysozyme (hLyz). Fluorescence spectroscopy revealed static quenching as the major mechanism in forming a stable CNC-hLyz complex, and the binding was energetically favorable. The obtained values of the thermodynamic parameters (AG, AH, and AS) proposed that the complex formation between the enzyme and cellulose nanocrystals is driven by electrostatic interactions, which were also confirmed by molecular dynamics (MD) simulation. Additionally, the MD simulation analysis displays that the enzyme's structural elements and tertiary structure were primarily maintained, and only loops regions were affected in the presence of cellulose nanocrystals. At the same time, circular dichroism (CD) outcomes highlighted that higher cellulose nanocrystals concentration caused a reduction in the secondary structure of hLyz. Our observations proved that low cellulose nanocrystals concentrations have no considerable effect on the human lysozyme structure. The current research results provide a valuable opportunity to elucidate the molecular interactions between protein and nanocelluloses, guiding further investigations of CNC-based material for biomedical, pharmaceutical, and food industry applications.