ABSTRACT
Objective To amplify four fragments of circumsporozoite ( CSP) protein gene from Plasmodium falciparum FCC1/HN strain and express recombinant CSP proteins in prokaryotic vector pET28 a/EGFP for further evaluation of their binding activities to hepatic cells .Methods Four pairs of primers were designed according to the cDNA sequence of CSP protein from Plasmodium falciparum FCC1/HN strain and used to amplify the gene fragments by PCR .The cloned gene fragments were inserted into pET28a/EGFP to construct the recombinant expression plasmids .The transformed E.coli BL21 strains carry-ing expression plasmids were induced by IPTG to express CPS proteins .The recombinant CSP proteins were purified with Ni2+chelating HiTrap HP column and detected by SDS-PAGE.The binding activities of the ex-pressed proteins to different tissues were also detected .Results Four gene fragments encoding CSP protein were successfully amplified and expressed in E.coil BL21 strain as fusion protein CSR1a-EGFP, CSR1b-EGFP, CSR2a-EGFP and CSR2b-EGFP with a relative molecular mass of about 39×103, 31×103, 33×103 and 30 ×10 3 , respectively .The purified fusion proteins reacted specifically with Plasmodium falciparum-posi-tive serum samples.Moreover, the recombinant protein CSR2a-EGFP could bind to the hepatic cells specif-ically rather than other cells.Conclusion The purified recombinant CSR2a-EGFP protein has a strong binding activity to hepatocytes , indicating its potential value as a targeting molecule for hepatic gene therapy .