title: A Plasmodium falciparum copper-binding membrane protein with copper transport motifs.
abstract: BACKGROUND
  Copper 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.
  
  
  METHODS
  PlasmoDB 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.
  
  
  RESULTS
  Six 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.
  
  
  CONCLUSIONS
  Plasmodium 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.
authors.affiliation: Biochemistry, University of KwaZulu-Natal, Carbis Road, Scottsville, 3209, South Africa.
authors.forename: David L
authors.initials: DL
authors.lastname: Choveaux
authors.forename: Jude M
authors.initials: JM
authors.lastname: Przyborski
authors.forename: J P Dean
authors.initials: JP
authors.lastname: Goldring
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry; D003001:Cloning, Molecular; D019295:Computational Biology; D003300:Copper / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C023548:copper-binding protein; D003300:Copper