Biochemical characterization of the recombinant schistosome tegumental protein SmALDH_312 produced in E. coli and baculovirus expression vector system

Abstract

Background: The heterologous expression of parasitic proteins is challenging because the sequence composition often differs significantly from host preferences. However, the production of such proteins is important because they are potential drug targets and can be screened for interactions with new lead compounds. Here we compared two expression systems for the production of an active recombinant aldehyde dehydrogenase (SmALDH_312) from Schistosoma mansoni, which causes the neglected tropical disease schistosomiasis.

Results: We produced SmALDH_312 successfully in the bacterium Escherichia coli and in the baculovirus expression vector system (BEVS). Both versions of the recombinant protein were found to be active in vitro, but the BEVS-derived enzyme showed 3.7-fold higher specific activity and was selected for further characterization. We investigated the influence of Mg²⁺, Ca²⁺ and Mn²⁺, and found out that the specific activity of the enzyme increased 1.5-fold in the presence of 0.5 mM Mg²⁺. Finally, we characterized the kinetic properties of the enzyme using a design-of-experiment approach, revealing optimal activity at pH 7.6 and 41°C.

Conclusions: Although, E. coli has many advantages, such as rapid expression, high yields and low costs, this system was outperformed by BEVS for the production of a schistosome ALDH. BEVS therefore provides an opportunity for the expression and subsequent evaluation of schistosome enzymes as drug targets.