Abstract: AIM:To understand the interaction between a195- kilodalton protein,P195, on the surface
of Plasmodium falciparum merozoite and human erythrocyte.METHODS:P195 was expressed in eight fragments
in E.coli. After being refolded,the expressed proteins were labelled with¹²⁵I,and incubated with
human erythrocytes.RESULTS:According to binding assay, three fragments of P195:M3,M6,M9were found to
have ability to bind to human erythrocyte. M6,which is equal to amino acid( AA) sequence from384
to595,could bind to human erythrocytes but not to trypsin treated human erythrocytes, and the binding could be eluted by low pH buffer solution. M3 (AA123 to 302) and M9 (AA1078 to 1251) also have the ability to bind to human erythrocytes, but the binding was not affected by trypsin treatment and low pH buffer elution. CONCLUSION: The binding site of M6 might be a surface protein recept or of human erythrocytes, while the binding site of M3 and M9 might be an intracellular component of human erythrocyte.

Key words: Plasmodium falciparum, P195, erythrocyte binding