Subcloning,sequencing and expressing of conserved blocks of P190 gene of Plasmodium falciparum FCC1/HN strain

190-kilodalton glycoprotein (P190) of Plasmodium falciparum,precursor of themajor surface protein of merozoites,is considered a promising candidate for blood stage malarialvaccine.Six primers were designed according to the sequence of MAD20 strain,with a GCclamp and BamH Ⅰ site at the 5’-end of each one,and a GC clamp and Xba Ⅰ site at the 3’-endof each one.The primers were synthesized by phosphoramidite approach (User’s Manual ofABI Company) and purified using HPLC.Three fragments in the second,third and fourth con-served regions of P190 gene of Plasrnodium falciparum FCC1/HN strain isolated from theblood of patients in Hainan Province of China were amplified by the polymerase chain reaction(PCR).The amplified fragments were suhcloned into pUC18 vectors and sequenced using thedideoxy chain termination method.All three regions of P190 gene of FCC1/HN strain also werehighly conservative as compared with P190 gene of MAD20 (Papua New Guinea isolate),K1(Thailand isolate),Wellcome (West Africa isolate) and CAMP (Malaysia) strains ofPlasmodium falciparum.The C at position 81 in the second conserved block of P190 gene ofFCC1/HN isolate was substituted by T,which did not change the amino acid determined by thecodon corresponding to the substitution.The genes sequenced were cloned into rpGEX-2T,aglutathione S-transferase gene fusion system for expression.