Characterization of the putative sterol sensing domain containing protein in Plasmodium falciparum

• Main Authors: Zhung-Liang Zhao, 趙仲良
• Other Authors: Yu-Tein Liu, Ph. D.
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/61166751031262442918

碩士 === 國防醫學院 === 微生物及免疫學研究所 === 91 === Abstract Cholesterol is an essential element to maintain cell membrane structure and function. However, Plasmodia are intracellular parasites and are incapable to carry out de novo cholesterol. They have to obtain this membrane component from their host erythrocyte. Recently, cholesterol has been shown transported by the rafts from the host cell membrane to the parasite vacuole membrane. It suggests that there would be a factor to modulate the cholesterol transport between the parasite vacuole membrane and the host cell membrane. Niemann-Pick type C1 disease is an abnormal accumulation of cellular cholesterol caused by the defect in NPC1 protein that is responsible for the cholesterol transport and homeostasis. To blast the malarial genome database with the human NPC1 gene had been shown that there was a NPC1 homologous gene in P. falciparum. In order to identify the PfNPC gene, the truncated sequence of PfNPC gene was cloned by RT-PCR and ligated into the expressive vector pGEX4T-1. After the transformation of E.coli BL21(DE3) codon plus RIL competent cell , the recombinant protein was produced, and then purified by the GST affinity column for immunizing rabbit. The antiserum against this PfNPC fusion protein had been used to prove the expression of PfNPC in P. falciparum infected erythrocyte. The PfNPC had also been proven as an integral membrane protein that interacted with cholesterol and possibly with human erythrocytic membrane channel protein Band 3. Comparing the predicted topology and the consistence of amino acids in PfNPC with the other SSD protein families, we proposed that either NPC1 or PTC1 shared similarity with PfNPC.