The causative agent of malaria, Plasmodium falciparum posses a single 
aquaglyceroporin (PfAQP) which represents a potential drug target for treatment 
of the disease. PfAQP is localized to the parasite membrane to transport water, 
glycerol, ammonia and possibly glycolytic intermediates. In order to enable 
design of inhibitors we set out to determine the 3D structure of PfAQP, where 
the first bottleneck to overcome is achieving high enough yield of recombinant 
protein. The wild type PfAQP gene was expressed to low or undetectable levels in 
the expression hosts, Escherichia coli and Pichia pastoris, which was assumed to 
be due to different genomic A+T content and different codon usage. Thus, two 
codon-optimized PfAQP genes were generated. The Opt-PfAQP for E. coli still did 
not result in high production yields, possibly due to folding problems. However, 
PfAQP optimized for P. pastoris was successfully expressed in P. pastoris for 
production and in Saccharomyces cerevisiae for functional studies. In S. 
cerevisiae, PfAQP mediated glycerol transport but unexpectedly water transport 
could not be confirmed. Following high-level membrane-localized expression in P. 
pastoris (estimated to 64mg PfAQP per liter cell culture) PfAQP was purified to 
homogeneity (18mg/L) and initial attempts at crystallization of the protein 
yielded several different forms.