title: Protein S-nitrosylation in Plasmodium falciparum.
abstract: OBJECTIVE
  Due to its life in different hosts and environments, the human malaria parasite Plasmodium falciparum is exposed to oxidative and nitrosative challenges. Nitric oxide (NO) and NO-derived reactive nitrogen species can constitute nitrosative stress and play a major role in NO-related signaling. However, the mode of action of NO and its targets in P. falciparum have hardly been characterized. Protein S-nitrosylation (SNO), a posttranslational modification of protein cysteine thiols, has emerged as a principal mechanism by which NO exerts diverse biological effects. Despite its potential importance, SNO has hardly been studied in human malaria parasites. Using a biotin-switch approach coupled to mass spectrometry, we systemically studied SNO in P. falciparum cell extracts.
  
  
  RESULTS
  We identified 319 potential targets of SNO that are widely distributed throughout various cellular pathways. Glycolysis in the parasite was found to be a major target, with glyceraldehyde-3-phosphate dehydrogenase being strongly inhibited by S-nitrosylation of its active site cysteine. Furthermore, we show that P. falciparum thioredoxin 1 (PfTrx1) can be S-nitrosylated at its nonactive site cysteine (Cys43). Mechanistic studies indicate that PfTrx1 possesses both denitrosylating and transnitrosylating activities mediated by its active site cysteines and Cys43, respectively.
  
  
  METHODS
  This work provides first insights into the S-nitrosoproteome of P. falciparum and suggests that the malaria parasite employs the thioredoxin system to deal with nitrosative challenges.
  
  
  CONCLUSIONS
  Our results indicate that SNO may influence a variety of metabolic processes in P. falciparum and contribute to our understanding of NO-related signaling processes and cytotoxicity in the parasites.
authors.affiliation: 1 Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University , Giessen, Germany .
authors.forename: Lihui
authors.initials: L
authors.lastname: Wang
authors.forename: Claire
authors.initials: C
authors.lastname: Delahunty
authors.forename: Judith Helena
authors.initials: JH
authors.lastname: Prieto
authors.forename: Stefan
authors.initials: S
authors.lastname: Rahlfs
authors.forename: Esther
authors.initials: E
authors.lastname: Jortzik
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.forename: Katja
authors.initials: K
authors.lastname: Becker
mesh_terms: D003545:Cysteine / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry; D009569:Nitric Oxide / Q000378:metabolism; D010963:Plasmodium falciparum / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000378:metabolism; D040901:Proteomics; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D026403:S-Nitrosothiols / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism
chemical_list: D011506:Proteins; D026361:Reactive Nitrogen Species; D026403:S-Nitrosothiols; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide; D013879:Thioredoxins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D003545:Cysteine