Isolation and Characterization of Type I Signal Peptidase ofDifferent Malaria Parasites

[摘要] Type I signal peptidases are important membrane-bound serineproteases responsible for the cleavage of the signal peptide ofthe proteins. These enzymes are unique serine proteases thatcarry out catalysis using a serine/lysine catalytic dyad. In thepresent study, we report the isolation of type I signal peptidasefrom the malaria parasitesPlasmodium falciparum,Plasmodium knowlesi, andPlasmodium yoeliiandsome characterization of type I signal peptidase ofPlasmodium falciparum. We show that these enzymes arehomologous to signal peptidases from various sources and alsocontain the conserved boxes present in other type I signalpeptidases. The type I signal peptidase fromP falciparumis an intron-less and a single-copy gene. The results also showthat the enzyme fromPlasmodium falciparumis subject toself-cleavage and it has been demonstrated to possess type Isignal peptidase activity inE colipreprotein processingin vivo by complementation assay. This study will be helpful inunderstanding one of the important metabolic pathways “thesecretory pathway” in the parasite and should make an importantcontribution in understanding the complex process of proteintargeting in the parasite.

[学科分类] 基础医学