A family of cathepsin B cysteine proteases expressed in the gut of the human hookworm, Necator americanus

Ranjit, Najju, Zhan, Bin, Stenzel, Deborah J., Mulvenna, Jason, Fujiwara, Ricardo, Hotez, Peter J. and Loukas, Alex (2008) A family of cathepsin B cysteine proteases expressed in the gut of the human hookworm, Necator americanus. Molecular and Biochemical Parasitology, 160 2: 90-99. doi:10.1016/j.molbiopara.2008.04.008


Author Ranjit, Najju
Zhan, Bin
Stenzel, Deborah J.
Mulvenna, Jason
Fujiwara, Ricardo
Hotez, Peter J.
Loukas, Alex
Title A family of cathepsin B cysteine proteases expressed in the gut of the human hookworm, Necator americanus
Formatted title
A family of cathepsin B cysteine proteases expressed in the gut of the human hookworm, Necator americanus
Journal name Molecular and Biochemical Parasitology   Check publisher's open access policy
ISSN 0166-6851
1872-9428
Publication date 2008-08
Sub-type Article (original research)
DOI 10.1016/j.molbiopara.2008.04.008
Volume 160
Issue 2
Start page 90
End page 99
Total pages 10
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Formatted abstract
mRNAs encoding cathepsin B-like cysteine proteases (CatBs) are abundantly expressed in the genomes of blood-feeding nematodes. Recombinant CatBs have been partially efficacious in vaccine trials in animal models of hookworm infection, supporting further investigation of these enzymes as new control tools. We recently described a family of four distinct CatBs (Na-CP-2, -3, -4, -5) from the human hookworm, Necator americanus. Here we show that these N. americanus CatBs form a robust clade with other hookworm CatBs and are most similar to intestinal CatBs from Haemonchus contortus. All four mRNAs (Na-cp-2, -3, -4 and -5) are up-regulated during the transition from a free-living larva to a blood-feeding adult worm and are also expressed in gut tissue of adult N. americanus that was dissected using laser microdissection microscopy. Recombinant Na-CP-3 was expressed in soluble, secreted form in the yeast Pichia pastoris, while Na-CP-2, -4 and -5 were expressed in insoluble inclusion bodies in Escherichia coli. Recombinant Na-CP-3 was not catalytically active when secreted by yeast but underwent auto-activation to an active enzyme at low pH in the presence of dextran sulphate. Activated Na-CP-3 digested gelatin and cleaved the fluorogenic substrate Z-Phe-Arg-aminomethylcoumarin (AMC) but not Z-Arg-Arg-AMC. Recombinant Na-CP-3 did not digest intact hemoglobin but digested globin fragments generated by prior hydrolysis with N. americanus aspartic hemoglobinases. Antibodies raised in mice to all four recombinant proteins showed minimal cross-reactivity with each other, and each antiserum bound to the intestine of adult N. americanus, supporting the intestinal expression of their mRNAs. These data show that N. americanus expresses a family of intestinal CatBs, many of which are likely to be involved in nutrient acquisition and therefore are potential targets for chemotherapies and vaccines.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: ERA 2012 Admin Only
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Created: Thu, 27 Oct 2011, 14:39:37 EST by Geraldine Fitzgerald on behalf of School of Public Health