RESUMO
<p><b>OBJECTIVE</b>To clone the catalytic domain gene sequence of RgpAcd of Porphyromonas gingivalis (P. gingivalis) and to induce its fusion expression in E. coli.</p><p><b>METHODS</b>The desired DNA fragment RgpAcd was obtained by PCR and was separately sequenced and identified by inserting into inter-vector pMD18-T vector. The correctly fragment was linked with and cloned into a prokaryotic expression vector pET-15b. The recombinant expression plasmid which had been confirmed by enzymes digestion was transformed to E. coli competent cells BL21 (DE3) and expression of fusion protein was induced by IPTG.</p><p><b>RESULTS</b>A 1 476 bp specific fragment was obtained and DNA sequencing showed that the fragment was consistent with those of the published. After induction with IPTG, a fusion protein of 5 x 10(4) was visualized on SDS-PAGE gel.</p><p><b>CONCLUSION</b>The protein of RgpAcd will be obtained for further study and its protein was correctly expressed in E. coli BL21 cells.</p>