A Plasmodium falciparum copper-binding membrane protein with copper transport motifsReport as inadecuate




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Malaria Journal

, 11:397

First Online: 29 November 2012Received: 03 October 2012Accepted: 20 November 2012

Abstract

BackgroundCopper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper still remains to be fully elucidated.

MethodsPlasmoDB was searched for sequences corresponding to candidate P. falciparum copper-requiring proteins. The amino terminal domain of a putative P. falciparum copper transport protein was cloned and expressed as a maltose binding fusion protein. The copper binding ability of this protein was examined. Copper transport protein-specific anti-peptide antibodies were generated in chickens and used to establish native protein localization in P. falciparum parasites by immunofluorescence microscopy.

ResultsSix P. falciparum copper-requiring protein orthologs and a candidate P. falciparum copper transport protein PF14 0369, containing characteristic copper transport protein features, were identified in PlasmoDB. The recombinant amino terminal domain of the transport protein bound reduced copper in vitro and within Escherichia coli cells during recombinant expression. Immunolocalization studies tracked the copper binding protein translocating from the erythrocyte plasma membrane in early ring stage to a parasite membrane as the parasites developed to schizonts. The protein appears to be a PEXEL-negative membrane protein.

ConclusionPlasmodium falciparum parasites express a native protein with copper transporter characteristics that binds copper in vitro. Localization of the protein to the erythrocyte and parasite plasma membranes could provide a mechanism for the delivery of novel anti-malarial compounds.

KeywordsMalaria Copper transporter Permeome PEXEL-negative AbbreviationsAtox1Antioxidant protein 1

BCABicinchoninic acid

CCOCytochrome-c oxidase

CCSCopper chaperone for superoxide dismutase

Ctr1Copper transport protein 1

Cu-Zn SODCuprozinc superoxide dismutase

Exp1Export protein 1

GAPDHGlyceraldehyde 3-phosphate dehydrogenase

H2 AscAscorbic acid

HSP 86-90Heat shock protein 86-90

LDHLactate dehydrogenase

MAHRP1Membrane-associated histidine-rich protein 1

MBPMaltose binding protein

PEXEL-HTPlasmodium export element-host targeting signal

Pf Ctr369NtPlasmodium falciparumcopper transport protein PF14 0369 amino terminal domain minus signal peptide

PNEPPEXEL negative exported protein

REX2Ring exported protein 2

SBP1Skeleton binding protein 1.

Electronic supplementary materialThe online version of this article doi:10.1186-1475-2875-11-397 contains supplementary material, which is available to authorized users.

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Author: David L Choveaux - Jude M Przyborski - JP Dean Goldring

Source: https://link.springer.com/







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