Polyprotein allergens of nematodes (NPAs): the case of ascaris suum and other parasitic nematodes

GISELA R. FRANCHINI

La Plata

Congreso; 8th International Conference on Lipid Binding Proteins; 2013

Infections with parasitic helminths cause severe debilitating and sometimes lethal diseases in humans and domestic animals on a global scale. Unable to synthesize their own fatty acids and sterols, helminth parasites (nematodes, trematodes, cestodes) rely on their hosts for their supply. The acquisition and transport of lipids is crucial to these organisms, and the proteins and their receptors involved in lipid transport and exchange provide potential targets for chemo- and immunotherapy. Among helminth lipid binding proteins (LBPs), the polyprotein allergens/antigens of nematodes (NPAs) represent a novel class of lipid binding proteins which has been described in nematodes. NPAs are small, helix-rich proteins, and have no known structural counterparts in other phyla, including the animals and plants in which parasitic nematodes cause so much harm. NPA of A. suum was first described as a binding protein for small lipids such as fatty acids and retinoids. Recently, the structure of a single unit of the polyprotein array has been solved in the presence of saturating concentration of oleic acid describing two binding sites. In the present project we are working with ABA-1A in the absence of the ligand (apo form) and its atomic structure is under analysis employing NMR spectroscopy, for which high quality data have already been obtained and full structure calculation is in progress. We aim at determining the naturally bound ligands of these proteins as well as their binding activity. Additionally, we are exploring for NPAs in the parasitic nematode Haemonchus contortus. Up to date, we have the complete mRNA and protein sequence using public databases and gene prediction softwares.