The chitinase (EC 3.2.1.14) of the human malaria parasite Plasmodium falciparum, PfCHT1, has been validated as a malaria transmission-blocking vaccine (TBV). The present study aimed to delineate functional characteristics of the P. vivax chitinase PvCHT1, whose primary structure differs from that of PfCHT1 by having proenzyme and chitin-binding domains. The recombinant protein rPvCHT1 expressed with a wheat germ cell-free system hydrolyzed 4-methylumbelliferone (4MU) derivatives of chitin oligosaccharides (beta-1,4-poly-N-acetyl glucosamine (GlcNAc)). An anti-rPvCHT1 polyclonal antiserum reacted with in vitro-obtained P. vivax ookinetes in anterior cytoplasm, showing uneven patchy distribution. Enzymatic activity of rPvCHT1 shared the exclusive endochitinase property with parallelly expressed rPfCHT1 as demonstrated by a marked substrate preference for 4MU-GlcNAc(3) compared to shorter GlcNAc substrates. While rPvCHT1 was found to be sensitive to the general family-18 chitinase inhibitor, allosamidin, its pH (maximal in neutral environment) and temperature (max. at approximately 25 degrees C) activity profiles and sensitivity to allosamidin (IC50=6 microM) were different from rPfCHT1. The results in this first report of functional rPvCHT1 synthesis indicate that the P. vivax chitinase is enzymatically close to long form Plasmodium chitinases represented by P. gallinaceum PgCHT1.
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http://dx.doi.org/10.1016/j.parint.2009.05.002 | DOI Listing |
Front Cell Infect Microbiol
December 2022
Laboratory of Malaria and Toxoplasmosis Biology, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
In the fight against malaria, the key is early treatment with antimalarial chemotherapy, such as artemisinin-based combination treatments (ACTs). However, has acquired multidrug resistance, including the emergence of strains with resistance to ACT. The development of novel antimalarial molecules, that are capable of interfering in the asexual and sexual blood stages, is important to slow down the transmission in endemic areas.
View Article and Find Full Text PDFMalar J
May 2022
Biology Department/Institute of Genomics and Evolutionary Medicine [iGEM], Temple University, Philadelphia, PA, 19122-1801, USA.
The global malaria burden sometimes obscures that the genus Plasmodium comprises diverse clades with lineages that independently gave origin to the extant human parasites. Indeed, the differences between the human malaria parasites were highlighted in the classical taxonomy by dividing them into two subgenera, the subgenus Plasmodium, which included all the human parasites but Plasmodium falciparum that was placed in its separate subgenus, Laverania. Here, the evolution of Plasmodium in primates will be discussed in terms of their species diversity and some of their distinct phenotypes, putative molecular adaptations, and host-parasite biocenosis.
View Article and Find Full Text PDFProtein Sci
August 2021
Tata Institute for Genetics and Society, Center at inStem, Bengaluru, India.
Malaria is a life-threatening disease caused by one of the five species of Plasmodium, among which Plasmodium falciparum cause the deadliest form of the disease. Plasmodium species are dependent on a vertebrate host and a blood-sucking insect vector to complete their life cycle. Plasmodium chitinases belonging to the GH18 family are secreted inside the mosquito midgut, during the ookinete stage of the parasite.
View Article and Find Full Text PDFParasit Vectors
March 2018
Diretoria de Ensino e Pesquisa, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, AM, Brazil.
Background: Plasmodium vivax is predominant in the Amazon region, and enhanced knowledge of its development inside a natural vector, Anopheles aquasalis, is critical for future strategies aimed at blocking parasite development. The peritrophic matrix (PM), a chitinous layer produced by the mosquito midgut in response to blood ingestion, is a protective barrier against pathogens. Plasmodium can only complete its life-cycle, and consequently be transmitted to a new host, after successfully passing this barrier.
View Article and Find Full Text PDFParasitol Int
September 2009
Cell-Free Science and Technology Research Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
The chitinase (EC 3.2.1.
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