Changes in secondary structure of protein in skeletal muscle due to high-carbohydrate or high-fat diets

Objective: Obesity, which arises from changes in lifestyle and feeding habits, poses a threat to human health. One essential contributor to the increase in obesity rates is the popularity of high-calorie diets. This study aims to investigate high-fat (HFD) and high-carbohydrate (HCD) diet-induced molecular changes in protein secondary structure in longissimus dorsi skeletal muscle tissues of female inbred C57BL/6J mice by utilizing Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Materials and Methods: Mice were fed a control diet, HCD, or HFD for 24 weeks. Their skeletal muscle tissues were collected, and their spectra were recorded using a Bruker Invenio S ATR-FTIR spectrometer in the 4000-400 cm-1 region. Results: The protein secondary structure profiles of the HCD group demonstrated a significant rise in antiparallel beta-sheet and beta-turn and a decline in parallel beta-sheets, together with the insignificant increase in aggregated beta-sheets and a decrease in alpha-helix. The impact of an HFD on protein conformation is less pronounced than HCD. The HFD diet led to an increase in antiparallel beta-sheets and a decrease in parallel beta sheets. Although insignificant, an increase was observed in beta-turn and alpha-helix. Conclusion: These results propose the appearance of protein aggregation and/or formation of protein- protein intermolecular interaction in skeletal muscle tissues of female inbred C57BL/6J mice. Collectively, these data suggest that both high-calorie diets impair secondary structures of protein in skeletal muscle that may affect its metabolic function.