Potential improvement of the thermal stability of sweet-tasting proteins by structural calculations. (30th May 2021)

• Record Type: Journal Article
• Authors: Tang, Ning; Liu, Jiachen; Cheng, Yongqiang
• Is Part Of: Food chemistry. Volume 345(2021)
• Publication Date: 2021-05-30
• Subjects: Saturation mutagenesis -- Thermal stability -- Sweet-tasting proteins -- Negatively charged; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2020.128750
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Saturation mutagenesis was performed for brazzein, curculin, monellin and thaumatin. The thermal stability can be predicted by the calculated ΔΔG values. The sweet-tasting proteins were mainly interacted with T1R2 VFT domain. Negatively charged residues were key residues for improving the thermal stability. Abstract: The low thermal stability of the sweet-tasting proteins limited their applications in food industry. Improve their thermal stability is the key to developing their applications in food processing. In the present study, saturation mutagenesis was performed on 4 sweet-tasting proteins, brazzein (988 mutations), curculin (2109 mutations), monellin (1824 mutations) and thaumatin (3933 mutations), using structural calculations in order to find more thermal stable mutations. The obtained results indicated that our calculated ΔΔG value (ΔΔG < 0 stabilizing, ΔΔG > 0 destabilizing) was a good predictor for predicting changes in thermal stability caused by mutations. Moreover, mutating the negatively charged residues to the other non-negatively charged amino acids was an efficient way to improve the thermal stability of the investigated sweet-tasting proteins. In addition, some promising mutations sites were identified for improving thermal stability using mutagenesis. This study provides useful information for future protein engineering to improve the thermal stability of the sweet-tasting proteins.