title: [Cloning of the fimA gene of Porphyromonas gingivalis and its expression and purification in Escherichia coli].
abstract: OBJECTIVE; To clone the fimA gene of Porphyromonas gingivalis (P. gingivalis) and detect its expression in Escherichia coli (E. coli).
  
  
  METHODS
  The fimA gene was obtained by PCR from the genome of P. gingivalis to construct a prokaryotic expression plasmid pT-BAD/fimA. pT-BAD/fimA was transformed into E. coli BL21 (DE3) competent cells and the recombination protein was characterized by means of matrix assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. The bound protein was eluted with different concentrations of imidazole (250, 200, 150, 100, 50 micromol x L(-1)) respectively.
  
  
  RESULTS
  DNA sequencing showed that the fragment was 99.9% consistent with that of the published. After induction with L-arabinose, a new 3.8 x 10(4) protein appeared on SDS-PAGE gel. The protein was further identified by MALDI-TOF-MS. Purity of 95% of the target protein was purified by Ni-NTA Purification System after eluted with 100 micromol x L(-1) imidazole.
  
  
  CONCLUSIONS
  The fimA gene of P. gingivalis was cloned successfully and its protein was expressed correctly in E. coli. A high purity of protein FimA was obtained and it could be applied for follow-up researches.
authors.affiliation: Center of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: He
mesh_terms: D019976:Cloning, Organism; D004926:Escherichia coli; D036781:Fimbriae Proteins; D010957:Plasmids; D016133:Polymerase Chain Reaction; D016966:Porphyromonas gingivalis
chemical_list: D036781:Fimbriae Proteins