Structural Analysis of the Catalytic Domain for the Plasmodium BEM46-Like Protein

Malaria parasites are obligatory intracellular protists in the genus Plasmodium that are transmitted by Anopheline mosquitoes. The liver-stage (LS) is a critical target for drug interventions as it results in a massive parasitic amplification event, producing thousands of blood-stage parasites that cause the symptomatic disease. In order to understand the morphological changes that occur on the parasite plasma membrane (PPM) during the mosquito- to liver-stage transition, we need to develop a more comprehensive understanding of the proteins implicated in LS development. The Plasmodium BEM46-like protein (PBLP) has been shown to be an important determinant for invasive-stage morphogenesis both in vitro and in vivo, although the enzymatic function of this protein has not yet been characterized. The bud emergence (BEM)46 proteins possess a conserved amino acid motif in the α/β-hydrolase superfamily that includes a variety of enzymes, although few have known biological functions. Here we examined the functional role of the catalytic domain of PBLP using protein structure prediction software. We were able to ascertain the putative active site of PBLP, which was consistent with the predicted active site proposed for other BEM46 proteins. In order to determine the function of PBLP, we cloned a cDNA copy of the pblp gene into a bacterial protein expression vector. Our goal is to express PBLP in Escherichia coli in order to purify and characterize its activity using functional enzymatic assays. Mutant PBLP constructs will be generated using overlap-extension PCR to verify the location of the putative active site as well as serve as a negative control in future enzymatic assays. Our aim is to gain a better understanding of the function of the catalytic domain of PBLP since it has the potential to be a major PPM target for novel drug intervention strategies.