title: [The binding property of different regions in Duffy-binding-like domain alpha of Plasmodium falciparum erythrocyte membrane protein 1 to heparin].
abstract: OBJECTIVE
  To clone and express Plasmodium falciparum erythrocyte membrane protein 1 DBLalpha (PfEMP1-DBLalpha) and three fragments genes, and screen the strongest affinity sequence with the red blood cell surface receptors-heparin or heparin sulfate in the structure of PfEMP1-DBLalpha.
  
  
  METHODS
  The sequence of PfEMP1-DBLalpha1245 was optimized according to the characteristics of E. coli codon, synthesized, and divided into three fragments (DBLaA, DBLalphaB, and DBLalphaC) by PCR. Full-length gene and three gene fragments were subcloned into PGEX-4T-1 vector, and transformed into E. coli BL21 and then induced with IPTG for expression. The recombinant protein was purified from bacterial lysates using glutathione-Sepharose 4B. Heparin affinity test and glycosaminoglycan (GAG) inhibition test were used to analyze the affinity between recombinant protein and heparin.
  
  
  RESULTS
  Four recombinant proteins(DBLalpha1245, DBLalphaA, DBLalphaB, and DBLalphaC) were expressed as solubility and the relative molecular weight (M(r) 73 600, M(r) 41 600, M(r) 42 500, and M(r) 41 500) were conformed to the prediction size. Heparin affinity test and GAG inhibition test showed that the four recombinant proteins were binded to the heparin-Sepharose, but not for the GST control. DBLalphaC (Q285-Y415) had the strongest affinity to heparin.
  
  
  CONCLUSIONS
  The strongest affinity sequence with heparin or heparin sulfate in the structure of PfEMP1-DBLalpha is Q285-Y415, which plays a role in binding of Plasmodium falciparum infected red blood cells to the peripheral red blood cells.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xi-Dong
authors.initials: XD
authors.lastname: Sun
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.forename: Ya-Na
authors.initials: YN
authors.lastname: Zhang
authors.forename: Meng
authors.initials: M
authors.lastname: Song
authors.forename: Hui-Jun
authors.initials: HJ
authors.lastname: Lu
authors.forename: Ning
authors.initials: N
authors.lastname: Jiang
authors.forename: Ji-Gang
authors.initials: JG
authors.lastname: Yin
authors.forename: Qi-Jun
authors.initials: QJ
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D004912:Erythrocytes / Q000469:parasitology*; D015870:Gene Expression; D006493:Heparin / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000235:genetics*; D011485:Protein Binding; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins; D011994:Recombinant Proteins; C085731:erythrocyte membrane protein 1, Plasmodium falciparum; D006493:Heparin