Crosslinking Mechanism on a Novel <i>Bacillus cereus</i> Transglutaminase-Mediated Conjugation of Food Proteins
Hongbin Wang,
Yuanfu Zhang,
Zhaoting Yuan,
Xiaotong Zou,
Yuan Ji,
Jiayi Hou,
Jinfang Zhang,
Fuping Lu,
Yihan Liu
Affiliations
Hongbin Wang
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Yuanfu Zhang
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Zhaoting Yuan
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Xiaotong Zou
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Yuan Ji
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Jiayi Hou
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Jinfang Zhang
Tianjin Key Laboratory of Industrial Microbiology, Tianjin 300457, China
Fuping Lu
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Yihan Liu
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
Until now, Streptoverticillium mobaraense transglutaminase (TG) is the only commercialized TG, but limited information is known about its selection tendency on crosslinking sites at the protein level, restricting its application in the food industry. Here, four recombinant Bacillus TGs were stable in a broad range of pH (5.0–9.0) and temperatures (B. cereus (BCETG) demonstrated the maximal specific activity of 177 U/mg. A structural analysis indicated that the Ala147-Ala156 region in the substrate tunnel of BCETG played a vital role in catalytic activity. Furthermore, bovine serum albumin, as well as nearly all protein ingredients in soy protein isolate and whey protein, could be cross-linked by BCETG, and the internal crosslinking paths of three protein substrates were elucidated. This study demonstrated Bacillus TGs are a candidate for protein crosslinking and provided their crosslinking mechanism at the protein level for applications in food processing.
