How the malaria parasite gets an essential amino acid

Amino acids are the building blocks of proteins. As it grows within its host red blood cell the malaria parasites utilizes large quantities of amino acids for this purpose. The malaria parasite derives most of its amino acid requirements from chopping up the haemoglobin of its host blood cell. But haemoglobin lacks one important amino acid, isoleucine, and the parasite therefore has to source this from elsewhere.

In this study we have shown that isoleucine is taken up into the infected blood cell from the external environment (the blood plasma), primarily via a novel channel induced by the parasite in the host red blood cell membrane. Having entered the infected cell isoleucine is rapidly taken up into the parasite via a sophisticated ‘transporter' mechanism that allows the parasite to take up isoleucine in exchange for another amino acid (leucine) which is the most abundant amino acid in haemoglobin and which the parasite therefore has in abundance. The transport pathways involved in isoleucine uptake play a crucial role in the parasite and are potential antimalarial drug targets.

Martin, R.E. and Kirk, K. (2007) Transport of the essential nutrient isoleucine in human erythrocytes infected with the malaria parasite Plasmodium falciparum. Blood, Prepublished online October 17, 2006; DOI 10.1182/blood-2005-11-026963 [Pubmed]