Triose phosphate isomerase from the blood fluke Schistosoma mansoni: Biochemical characterisation of a potential drug and vaccine target

Abstract

a b s t r a c tThe glycolytic enzyme triose phosphate isomerase from Schistosoma mansoni is a potential target for drugs and vaccines. Molecular modelling of the enzyme predicted that a Ser-Ala-Asp motif which is believed to be a helminth-specific epitope is exposed. The enzyme is dimeric (as judged by gel filtration and cross-linking), resistant to proteolysis and highly stable to thermal denaturation (melting temperature of 82.0°C). The steady-state kinetic parameters are high (K m for dihydroxyacetone phosphate is 0.51 mM; K m for glyceraldehyde 3-phosphate is 1.1 mM; k cat for dihydroxyacetone phosphate is 7800 s À1 and k cat for glyceraldehyde 3-phosphate is 6.9 s À1). Structured summary of protein interactions:SmTPI and SmTPI bind by cross-linking study (View interaction) SmTPI and SmTPI bind by molecular sieving (View interaction)

UDP-galactose 4′-epimerase from the liver fluke,Fasciola hepatica: biochemical characterization of the enzyme and identification of inhibitors

“…The complete coding sequence was obtained by DNA sequencing (GATC Biotech, London, UK). FhGALE protein was expressed in, and purified from, E. coli Rosetta(DE3) (Merck) using the same method as previously reported for F. hepatica triose phosphate isomerase and glyceraldehyde 3-phosphate dehydrogenase (Zinsser et al 2013; Zinsser et al 2014). …”

“…Analytical gel filtration and thermal scanning fluorimetry were carried out as previously described (Banford et al 2013; McCorvie et al 2013; Zinsser et al 2013; Zinsser et al 2013; Zinsser et al 2014). Protein concentrations were estimated by the method of Bradford using BSA as a standard (Bradford 1976).…”

Metabolic enzymes of helminth parasites: potential as drug targets

“…TPI from the trematodes F. hepatica and S. mansoni have both been biochemically characterised [117,118]. Phosphoenolpyruvate (Scheme 3) is an inhibitor of F. hepatica TPI; this inhibition is approximately 10-fold weaker than observed with the human enzyme [117,119].…”

“…Phosphoenolpyruvate (Scheme 3) is an inhibitor of F. hepatica TPI; this inhibition is approximately 10-fold weaker than observed with the human enzyme [117,119]. The structures of the enzyme from both species have been modelled and the S. mansoni enzyme contains a small loop on the surface (Ser-157 to Asp-159) which is not present in the human enzyme; this may be a site for immune recognition of the parasite enzyme [118,120]. Otherwise, the fluke enzymes show high predicted structural similarity to the human ones [117,118].…”

“…The structures of the enzyme from both species have been modelled and the S. mansoni enzyme contains a small loop on the surface (Ser-157 to Asp-159) which is not present in the human enzyme; this may be a site for immune recognition of the parasite enzyme [118,120]. Otherwise, the fluke enzymes show high predicted structural similarity to the human ones [117,118]. In a number of unicellular parasites, covalent modification of TPI at surface-exposed cysteine residues has proved to be a successful strategy for the identification of species-specific TPI inhibitors [121][122][123][124][125][126][127][128].…”