Effects of temperature and pH on the structure of a metalloprotease from Lactobacillus fermentum R6 isolated from Harbin dry sausages and molecular docking between protease and meat protein.

ABSTRACT

BACKGROUND: Microbial protease can interact with meat protein in fermented meat products at a certain pH and temperature. To investigate the effects of various pH values and temperatures on the structural characteristics of Lactobacillus fermentum R6 protease, which was isolated from Harbin dry sausages, spectroscopy techniques and molecular dynamics were utilized to evaluate structural changes. RESULTS: The protease exhibited a stable spatial structure at pH 7 and 40 °C, and the extension of the protease structure was also promoted. Although the structure of the protease could be changed or destroyed by pH 8 and 70 °C, it was mainly determined by the changes of secondary and tertiary structures such as α-helix, ß-sheet, ß-turn and random coil. In addition, carbonyl vibration, -NH vibration, C-H stretching vibration and disulphide bonds were present in L. fermentum R6 protease under various pH and temperature conditions. Molecular docking showed that the protease can interact with myosin light chain, myosin heavy chain, actin and myoglobin. CONCLUSION: The protease can maintain stable structure and interact with meat protein, which reflected certain application prospects in the fermentation of Harbin dry sausages. © 2021 Society of Chemical Industry.