The characteristics of Lactobacillus curvatus R5 protease at different pH and temperature levels: structural change, molecular dynamics simulation, hydrolysis ability were extracted from Harbin dry sausage.

2025-09
International journal of biological macromolecules 321

PubMed: 40701460
DOI: 10.1016/j.ijbiomac.2025.146189

Study Design

Methods: Fourier transform infrared spectroscopy, circular dichroism, UV-Vis, and fluorescence spectroscopy were employed to assess structural alterations under different conditions; molecular dynamics simulations assessed root mean square deviation (RMSD), root mean square fluctuation (RMSF), hydrogen bond count, secondary structure, gyrate radius, and solvent accessible surface area; the study also explored the hydrolysis degree, soluble peptide content, solubility, degradation, and microstructure of MP hydrolyzed by L. curvatus R5 protease following different treatments.

This study investigated the structural properties of a protease isolated from Harbin dry sausages, specifically Lactobacillus curvatus R5, across various pH and temperature conditions. Fourier transform infrared spectroscopy, circular dichroism, UV-Vis, and fluorescence spectroscopy were employed to assess structural alterations under different conditions. The protease exhibited a stable spatial structure at pH 6 and 40 °C; however, deviations from these parameters induced structural changes, with the structure being compromised at 70 °C and pH 8. These changes were primarily attributed to alterations in the secondary structure, including α-helix, β-sheet, β-turns, and random coil. The protease displayed disulfide bonds, -NH vibrations, carbonyl vibrations, and CH stretching vibrations across the tested pH and temperature ranges. Molecular dynamics simulations assessed root mean square deviation (RMSD), root mean square fluctuation (RMSF), hydrogen bond count, secondary structure, gyrate radius, and solvent accessible surface area of L. curvatus R5. The study also explored the hydrolysis degree, soluble peptide content, solubility, degradation, and microstructure of MP hydrolyzed by L. curvatus R5 protease following different treatments. This research establishes a foundation for understanding the interplay between pH, temperature, and protease structure. The findings revealed that the protease maintained a stable structure and potent hydrolytic capacity at pH 6 and 40 °C, making it suitable for producing Harbin dry sausage.

Research Insights

Supplement	Dose	Health Outcome	Effect Type	Effect Size	Source
Lactobacillus curvatus	—	Improved Protein Hydrolysis Capacity	Beneficial	Moderate	View source The findings revealed that the protease maintained a stable structure and potent hydrolytic capacity at pH 6 and 40 °C, making it suitable for producing Harbin dry sausage.