Microbial transglutaminase from Streptomyces mobaraensis (MTG) has been widely used in food industry and also in research and medical applications, since it can site-specifically modify proteins by the cross-linking reaction of glutamine residue and the primary amino group. The recombinant expression system of MTG in E. coli provides better accessibility for the researchers and thus can promote further utilization of MTG. Herein, we report production of active and soluble MTG in E. coli by using a chimeric protein of tobacco etch virus (TEV) protease and MTG zymogen. A chimera of TEV protease and MTG zymogen with native propeptide resulted in active MTG contaminated with cleaved propeptide due to the strong interaction between the propeptide and catalytic domain of MTG. Introduction of mutations of K9R and Y11A to the propeptide facilitated dissociation of the cleaved propeptide from the catalytic domain of MTG and active MTG without any contamination of the propeptide was obtained. The specific activity of the active MTG was 22.7 ± 2.6 U/mg. The successful expression and purification of active MTG by using the chimera protein of TEV protease and MTG zymogen with mutations in the propeptide can advance the use of MTG and the researches using MTG mediated cross-linking reactions.

莫巴拉链霉菌（MTG）的微生物转谷氨酰胺酶由于可以通过谷氨酰胺残基和伯氨基的交联反应而定点修饰蛋白质，因此已广泛用于食品工业以及研究和医学应用。MTG在大肠杆菌中的重组表达系统为研究人员提供了更好的可及性，因此可以促进MTG的进一步利用。在此，我们报告了大肠杆菌中活性和可溶性MTG的产生通过使用烟草蚀刻病毒（TEV）蛋白酶和MTG酶原的嵌合蛋白。TEV蛋白酶和MTG酶原与天然前肽的嵌合体导致活性MTG被裂解的前肽污染，这是由于前肽与MTG催化域之间的强相互作用所致。将K9R和Y11A突变引入前肽，可以使裂解的前肽从MTG和活性MTG的催化结构域解离，而不会污染前肽。活性MTG的比活性为22.7±2.6U / mg。利用TEV蛋白酶的嵌合蛋白和前肽中具有突变的MTG酶原来成功表达和纯化活性MTG，可以促进MTG的应用和MTG介导的交联反应的研究。