Abstract:

Abstract:Objective To  extract and purify the  rombinant protein LTB-FAP of  fimbria of Actinobacillus actinomy cetecomitans which can be expressed in E.coli. and lay a foundation for its application in the treatment of periodontal diseases.Methods The constructed recombinant plasmid of  pET28a/LTB and pET28a/LTB-FAP  were  transformed into E.coli and the inclusion body of recombinant protein LTB-FAP was expressed. The recombinant protein was washed and dissolved by 2,4,6 and 8 mol·L^-1 urea;and then the dissolved protein was purified by both anion exchange chromatography and gel filtration chromatography;the concentration ofthe purified protein LTB-FAP was measured by thin layer chromatogram scanner.Results The inclusion body of the expressed protein was washed 3 times by 4 mol·L^-1 urea solution and dissloved in 6 mol·L^-1 urea solution,and 60% of the LTB-FAP protein could  be gotten. The purity of the recombinant protein LTB-FAP  purified in this experiment by anion exchange chromatography was about   75%;the puity of recombinant protein  LTB-FAP  was  90% by gel filtration chromatography. Conclusion The anion exchange chromatography and gel filtration chromatography can extract and purify the expressed recombinant protein LTB-FAP which can be used to immunize animal bodys. 

Key words:  Actinobacillus actinomycetemcomitans;LTB-FAP;extraction;purification