Expression of recombinant glucan binding protein B of S. mutans in E. coli and its purification

Objectives: To express and purify the recombinant glucan binding protein B of Streptococcus mutans in Escherichia coli. Methods: The DNA fragment encoding the glucan binding protein B of S. mutans was inserted into expression vector pPROEXTMHTb following ATG and a 6 histidine for affinity purification. The recombinant plasmid was transformed into E. coli BL21 (DE3) and induced by IPTG to express fusion protein. The recombinant protein was purified by metal-chelate affinity chromatography on Ni-NTA resin. Results: After induction with IPTG for 3 hour, a new foreign protein band near Mr 4.5°«5.0°Á103 appeared on SDS-PAGE. The purification rate of the recombinant protein was more than 95%. Conclusion: The recombinant glucan binding protein B of S. mutans was successfully expressed in E. coli BL21 (DE3) and purified. These make it possible for further study.