Falcipain-1, a Plasmodium falciparum cysteine protease with vaccine potential

Chauhan, Virander Singh ; Kumar, Amit ; Kumar, Krishan ; Korde, Reshma ; Puri, Sunil Kumar ; Malhotra, Pawan (2007) Falcipain-1, a Plasmodium falciparum cysteine protease with vaccine potential Infection and Immunity, 75 (4). pp. 2026-2034. ISSN 0019-9567

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Official URL: http://iai.asm.org/cgi/content/abstract/75/4/2026

Related URL: http://dx.doi.org/10.1128/IAI.01533-06


Cysteine proteases (falcipains) of Plasmodium falciparum are potential targets for antimalarial chemotherapy, since they have been shown to be involved in important cellular functions such as hemoglobin degradation and invasion/rupture of red blood cells during parasite life cycle. The role of falcipain-1 at the asexual blood stages of the parasite still remains uncertain. This is mainly due to a lack of methods to prepare this protein in an active form. In order to obtain biologically active falcipain-1, a number of falcipain-1 constructs were designed and a systematic assessment of the refolding conditions was done. We describe here the expression, purification, and characterization of a falcipain-1 construct encoding mature falcipain-1 and 35 amino acids from the C-terminal of the pro domain. Recombinant falcipain-1 was overexpressed in the form of inclusion bodies, solubilized, and purified by Ni2+-nitrilotriacetic acid affinity chromatography under denaturing conditions. A systemic approach was then followed to optimize refolding parameters. An optimum refolding condition was obtained, and the yield of the purified refolded falcipain-1 was ~1 mg/liter. Activity of the protein was analyzed by fluorometric and gelatin degradation assays. Immunolocalization studies using anti-falcipain-1 sera revealed a distinct staining at the apical end of the P. falciparum merozoites. Previous studies using falcipain-1-specific inhibitors have suggested a role of falcipain-1 in merozoite invasion. Based on its localization and its role in invasion, we analyzed the immunogenicity of falcipain-1 in mice, followed by heterologous challenge with Plasmodium yoelii sporozoites. Our results suggest a possible role of falcipain-1 in merozoite invasion.

Item Type:Article
Source:Copyright of this article belongs to American Society for Microbiology.
ID Code:8278
Deposited On:26 Oct 2010 11:52
Last Modified:16 May 2016 18:18

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