We have previously reported the purification and preliminary X-ray characterization of a hemagglutinin from the seeds of Jatropha curcas and, with the detailed sequencing information available now, we find that it is similar to a 2S albumin allergen isolated from the same source. Through a search of Jatropha genome database (http://www.kazusa.or.jp/jatropha/), we map it to the sequence id JcCA0234191 (now referred to as Jcr4S00619.70 in the new version, release 4.5) which has a conserved alpha amylase inhibitor/seed storage protein domain found in the 2S albumin allergens. The putative sequence of the small and large chains of the protein is assigned and the total mass of the two subunits matches with the intact mass 10 kDa determined through MALDI. The protein retains hemagglutination activity between pH 6-9 and up to 60 °C on heat treatment and its hemagglutination activity is inhibited by sialic acid and fetuin. Bioinformatics studies show that the isolated protein sequence clusters in close association with a 2S albumin from Ricinus communis in phylogeny analysis and has a conservation of the characteristic four disulfide linkage pattern. Hemagglutinins and lectins are known to have allergenic effects through their interaction with immunoglobulin E and histamine release and earlier studies have shown that this interaction can be inhibited by lectin-specific sugars. We hope this report bridges the plant allergens and hemagglutinins further for exploring possible mediation of allergenic activity through sialic acid and complex sugar interactions and generates further interest in the area.

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Malaria is the one most important parasitic disease of humans, which affects approximately one hundred countries and threatens half of the world's population. The Plasmodium aspartic protease called plasmepsins performs a vital role in providing nutrients to the malaria parasite, which make these proteins as an excellent drug target. In this study, we have carried out a comparative protein modeling, active site analysis and structural analysis of all ten plasmepsins from Plasmodium falciparum. In this report we have analyzed in-silico structure modeling and made efforts to characterize plasmepsins structure and further propose its functional information. The phylogenetic analysis and disulfide linkages indicate, plasmepsin I to IV and HAP have similar structure, function property. Whereas, plasmepsin IX to X and plasmepsin VI to VIII belong to a separate cluster. The integral membrane protein plasmepsin V has a functional characterization as compared to the others aspartic proteases from Plasmodium falciparum. The overall study summarizes the need of good model to understand the structure and function activity and to design potent small molecule inhibitors targeting all ten plasmepsins, specifically Plasmepsin V as important target.

The plant Jatropha curcas (Euphorbiaceae) is an important source of biofuel from the inedible oil present in its toxic seeds. The toxicity arises from the presence of curcin, a ribosome-inactivating protein showing haemagglutination activity. In this communication, the purification, crystallization and preliminary X-ray characterization are reported of a small protein isolated from J. curcas seeds with a molecular mass of ~10 kDa that agglutinates rabbit erythrocytes. The protein was crystallized using the hanging-drop vapour-diffusion method and also by the microbatch method in 72-well HLA plates, using PEG 8000 as the precipitant in both conditions. X-ray diffraction data collected from the rod-shaped crystals were processed in the orthorhombic space group P2(1)2(1)2(1). The crystals diffracted to 2.8 Å resolution at 103 K.

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