人工设计二硫键增强谷氨酰胺转胺酶热稳定性

Enhancement of the Thermostability of Transglutaminase from Streptomyces hygroscopicus by Engineering a Disulfide Bond

对S.hygroscopicus来源的谷氨酰胺转胺酶(microbial transglutaminase,MTG)进行分子改造,在MTG的N端区域引入二硫键,增强其热稳定性。通过序列比对与结构分析、运用Disulfide by Design软件,构建含有二硫键的突变体MTG(4-284)。在55℃下处理10 min,MTG(4-284)可以保持95%的酶活,而原始酶MTG仅剩15%的酶活。圆二色谱检测结果显示MTG和MTG(4-284)的T50分别为58和65℃。以上结果对MTG的分子水平的深入研究提供了基础,同时进一步满足其工业化应用的需求。

In this study, transglutaminase（MTG） from S. hygroscopicus was molecularly modified to improve the thermostability. Mutant MTG（4-284） containing a disulfide bond in the N-terminal region was constructed through sequence aligment, structure analysis and the software Disulfide by Design. After treatment at 55 ℃ for 10 min, MTG（4-284） remained 95% activity whereas MTG only retained 15% activity. The T50 values of MTG and MTG（4-284） were 58 and 65 ℃, respectively.Results in this study could improve genetic reconstruction and promote the industry application of MTG.