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U.S. Department of Health and Human Services

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Exp Parasitol 2011 Jan;127(1):1-8

Plasmodium falciparum: nitric oxide modulates heme speciation in isolated food vacuoles.

Ostera G, Tokumasu F, Teixeira C, Collin N, Sa J, Hume J, Kumar S, Ribeiro J, Lukat-Rodgers GS, Rodgers KR


Nitric oxide (NO) and NO-derived reactive nitrogen species (RNS) are present in the food vacuole (FV) of Plasmodium falciparum trophozoites. The product of PFL1555w, a putative cytochrome b(5), localizes in the FV membrane, similar to what was previously observed for the product of PF13_0353, a putative cytochrome b(5) reductase. These two gene products may contribute to NO generation by denitrification chemistry from nitrate and/or nitrite present in the erythrocyte cytosol. The possible coordination of NO to heme species present in the food vacuole was probed by resonance Raman spectroscopy. The spectroscopic data revealed that in situ generated NO interacts with heme inside the intact FVs to form ferrous heme nitrosyl complexes that influence intra-vacuolar heme solubility. The formation of heme nitrosyl complexes within the FV is a previously unrecognized factor that could affect the equilibrium between soluble and crystallized heme within the FV in vivo.

Category: Journal Article
PubMed ID: #20493843 DOI: 10.1016/j.exppara.2010.05.006
Includes FDA Authors from Scientific Area(s): Biologics
Entry Created: 2011-10-03 Entry Last Modified: 2012-08-29