Expression of antiª²prostate cancer polypeptide in Escheriachia coli

    LI Bin1, HAO Xiaoª²Ke1, LI Liª²Wen2, SU Mingª²Quan1, JIANG Nanª²Yan1

    1Department of Clinical Laboratory, 2PLA Institute of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To express a novel polypeptide for antiª²prostate cancer. METHODS: The polypeptide drug was designed based on the amino sequences of BH3, K237, DG2 domain and peptide that could be digested by PSA. The coding sequence of the drug was obtained by backª²translation using preferred codons of E.coli and chemically synthesized in nine oligonucleotides. The whole sequence was then constructed by phosphorylation, annealing and ligating into EcoR I and BamH I site of pGEXª²4Tª²2 expression vector, and was confirmed by restriction enzyme digestion and DNA sequencing. After the recombinant bacteria was induced at 37¡æ for 5 h, the expression protein was analyzed by SDSª²PAGE. RESULTS: After digested with BamH I and EcoR I, pGEX 4Tª²2ª²APP216 yielded a fragment of 216 bp just as we predicted. DNA sequencing result verified that the sequence of pGEX 4Tª²2ª²APP216 was consistent with what we had designed. SDSª²PAGE analysis demonstrated that protein was expressed in E.coli. The protein band amounted to 30% of total bacteria protein. CONCLUSION: The polypeptide is successfully expressed in E.coli. ......