[Identification of the binding site on glycophorin A for Plasmodium falciparum EBA-175].
OBJECTIVE
To identify the binding site on glycophorin A (GPA) for EBA-175 to provide clue for developing short peptide vaccine and therapeutic agents against Plasmodium falciparum.


METHODS
With the recombinant protein of EBA-175 as the target molecule, the mimetic peptides of GPA were screened from a 12-mer random peptide library. Three rounds of biopanning were carried out, and enzyme-linked immunosorbent assay (ELISA), competitive ELISA, Dot-ELISA and Western blotting used to evaluate the binding between the phage-borne peptides and EBA-175. The insert DNA sequences of positive clones were determined and their amino acid sequences deduced.


RESULTS
Thirty clones from the third round were randomly selected, of which 27 were found positive by sandwich ELISA. Competitive ELISA proved that most of the phage-borne peptides could competitively inhibit the binding of antibody (EBA-175 Ab) with EBA-175. Analysis of DNA and amino acid sequences indicated that 24 positive phage clones contained the conservative sequence of IRR, which was highly homologous with the 114-116 amino acids of GPA.


CONCLUSIONS
These phage-displayed peptides can bind with EBA-175, and the amino acid sequence IRR might play an important role in the binding between EBA-175 and GPA.
Sun
Xiao-min
XM
School of Biotechnology, Southern Medical University, Guangzhou 510515, China. Min1980@fimmu.com
Hao
Wen-bo
WB
Li
Ming
M
Luo
Ren
R
Jia
Yu-hua
YH
D000953:Antigens, Protozoan / Q000378:metabolism*; D001665:Binding Sites; D004797:Enzyme-Linked Immunosorbent Assay; D006021:Glycophorins / Q000737:chemistry*; D006801:Humans; D019151:Peptide Library; D010963:Plasmodium falciparum; D015800:Protozoan Proteins / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein
D000953:Antigens, Protozoan; D006021:Glycophorins; D019151:Peptide Library; D015800:Protozoan Proteins; C065668:erythrocyte-binding antigen 175, Plasmodium