College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Xianning Vocational Technical College, Xianning 437100, China.
J Agric Food Chem. 2024 Apr 3;72(13):7374-7382. doi: 10.1021/acs.jafc.3c09616. Epub 2024 Mar 25.
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.
巴西甜蛋白（Brazzein，Brz）是一种由 54 个氨基酸组成的甜味蛋白，被认为是一种有潜力的蔗糖替代品。目前获得巴西甜蛋白的方法较为复杂，且有关其热稳定性的信息有限。本研究成功表达了重组巴西甜蛋白，其甜度阈值达到 15.2 μg/mL。随后，我们对蛋白进行了 80、90、95 和 100°C 持续 2 小时的热处理，以研究蛋白结构的变化。此外，我们还采用氢氘交换结合质谱（HDX-MS）分析了加热对蛋白结构-甜度关系的影响。结果表明，热失活过程主要影响巴西甜蛋白的 6-14 位和 36-45 位氨基酸残基，特别是与甜度密切相关的关键残基 Tyr8、Tyr11、Ser14、Glu36 和 Arg43。这些发现对于提高巴西甜蛋白的热稳定性具有重要意义。
