Brazzein(Brz)是一种由54个氨基酸组成的甜味蛋白质,被认为是潜在的糖替代品。目前获得Brazzein的方法很复杂,关于其热稳定性的信息有限。在这项研究中,我们成功地表达了重组Brazzein,达到15.2μg/mL的甜度阈值。随后,我们在80、90、95和100°C的温度下进行了2小时的热处理,以研究蛋白质的结构变化。此外,我们使用氢-氘交换耦合质谱(HDX-MS)来分析加热对蛋白质结构-甜度关系的影响。我们的结果表明,热灭活过程主要影响Brazzein的残基6-14和36-45,特别是关键残基Tyr8,Tyr11,Ser14,Glu36和Arg43,它们与甜味密切相关。这些发现对于提高Brazzein的热稳定性具有重要意义。
Brazzein (Brz) is a sweet-tasting protein composed of 54 amino acids and is considered as a potential sugar substitute. The current methods for obtaining brazzein are complicated, and limited information is available regarding its thermal stability. In this
study, we successfully expressed recombinant brazzein, achieving a sweetness threshold of 15.2 μg/mL. Subsequently, we conducted heat treatments at temperatures of 80, 90, 95, and 100 °C for a duration of 2 h to investigate the structural changes in the protein. Furthermore, we employed hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS) to analyze the effect of heating on the protein structure-sweetness relationships. Our results indicated that the thermal inactivation process primarily affects residues 6-14 and 36-45 of brazzein, especially key residues Tyr8, Tyr11, Ser14, Glu36, and Arg43, which are closely associated with its sweetness. These findings have significant implications for improving the thermal stability of brazzein.