HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 277, Issue 17, 14514-14520, April 26, 2002

This Article Full Text Full Text (PDF) All Versions of this Article: 277/17/14514    most recent M109386200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mashima, R. Articles by Stocker, R. Search for Related Content PubMed PubMed Citation Articles by Mashima, R. Articles by Stocker, R. Social Bookmarking                      What's this?

Plasmodium falciparum Histidine-rich Protein-2 (PfHRP2) Modulates the Redox Activity of Ferri-protoporphyrin IX (FePPIX)
PEROXIDASE-LIKE ACTIVITY OF THE PfHRP2-FePPIX COMPLEX^*

Ryuichi Mashima^§, Leann Tilley^¶, Mary-Anne Siomos^¶, Vicki Papalexis^¶, Mark J. Raftery, and Roland Stocker^**

From the  Biochemistry Group, The Heart Research Institute, 145 Missenden Road, Camperdown, New South Wales 2050, the ^¶ Department of Biochemistry, La Trobe University, Bundoora, Victoria 3086, and the  Cytokine Research Unit, School of Pathology, University of New South Wales, Kensington, New South Wales 2052, Australia

Histidine-rich protein-2 from Plasmodium falciparum (PfHRP2) binds up to 50 molecules of ferri-protoporphyrin IX (FePPIX) (Choi, C. Y., Cerda, J. F., Chu, H. A., Babcock, G. T., and Marletta, M. A. (1999) Biochemistry 38, 16916-16924). We reasoned that the PfHRP2-FePPIX complex has antioxidant properties that could be beneficial to the parasite. Therefore, we examined whether binding to PfHRP2 modulated the redox properties of FePPIX. We observed that PfHRP2 completely inhibited the auto-oxidation of ascorbate mediated by free FePPIX. We also investigated the peroxidase activity of PfHRP2-FePPIX using 13-hydroperoxy-9,11-octadienoate (18:2-OOH) as substrate. Reaction of PfHRP2-FePPIX with 18:2-OOH in the presence of added reducing agents gave 13-hydroxy-9,11-octadienoate (18:2-OH) as a major product and 13-keto-9,11-octadienoate (18:2=O) and 9,12,13-trihydroxy-10-octadecaenoate as minor products. Binding of FePPIX to PfHRP2 lowered the rate of decomposition of 18:2-OOH and increased the 18:2-OH to 18:2=O ratio. Similar to other authentic peroxidases, phenols, amines, and biological reductants like ascorbate promoted 18:2-OH production, and NaCN inhibited 18:2-OH production. Thioanisole also acted as a reductant and was converted to thioanisole sulfoxide, suggesting formation of compound I during the reaction. These data show that PfHRP2 modulates the redox activity of FePPIX and that the PfHRP2-FePPIX complex may have previously unrecognized antioxidant properties.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				C. Spycher, N. Klonis, T. Spielmann, E. Kump, S. Steiger, L. Tilley, and H.-P. Beck MAHRP-1, a Novel Plasmodium falciparum Histidine-rich Protein, Binds Ferriprotoporphyrin IX and Localizes to the Maurer's Clefts J. Biol. Chem., September 12, 2003; 278(37): 35373 - 35383. [Abstract] [Full Text] [PDF]

				N. Campanale, C. Nickel, C. A. Daubenberger, D. A. Wehlan, J. J. Gorman, N. Klonis, K. Becker, and L. Tilley Identification and Characterization of Heme-interacting Proteins in the Malaria Parasite, Plasmodium falciparum J. Biol. Chem., July 18, 2003; 278(30): 27354 - 27361. [Abstract] [Full Text] [PDF]