Fatty acid- and retinol-binding (FAR) proteins are a structurally novel class of ~20 kDa lipid-binding proteins that are only found in nematodes. They belong to a family of proteins that exist in around seven different isoforms in each species and which are differentially produced at different life-cycle and developmental stages (Kennedy et al.
; Garofalo, Kennedy et al.
). They are hypothesized to play roles in host–parasite interaction and pathogenesis through the sequestration or delivery of pharmacologically or immunologically active small lipids, although there is still much to learn about their biological functions. Pertinent to this, FAR proteins have been found to be prominent components of the secretions of nematode parasites of humans, other animals and plants (Kennedy et al.
; Suire et al.
; Basavaraju et al.
). Their structures are predicted to be rich in α-helices and they have no structural counterparts in other animal groups (Kennedy et al.
; Basavaraju et al.
). The crystal structure of one FAR protein, Ce-FAR-7, from the free-living nematode Caenorhabditis elegans
has recently been reported (Jordanova et al.
). However, according to sequence comparison this protein belongs to a separate group within the FAR protein family that differs from those secreted by parasitic nematodes into host tissues (Garofalo, Rowlinson et al.
). FAR proteins, which are already used as diagnostic tools (Burbelo et al.
), are attractive potential targets for drug or vaccine development to generate new antihelminthic controls.
is a blood-feeding nematode hookworm which causes anaemia and growth stunting, infecting 750 million people in tropical and subtropical areas with poor hygiene and economic conditions (Hotez et al.
). Among the genes transcribed at high levels by N. americanus
, one that encodes a FAR protein, Na-FAR-1, has been identified (Daub et al.
Here, we report the bacterial expression of recombinant Na-FAR-1, its purification and its crystallization in two different space groups: P432 and F23.