title: Functional and bioinformatics analysis of two Campylobacter jejuni homologs of the thiol-disulfide oxidoreductase, DsbA.
abstract: BACKGROUND
  Bacterial Dsb enzymes are involved in the oxidative folding of many proteins, through the formation of disulfide bonds between their cysteine residues. The Dsb protein network has been well characterized in cells of the model microorganism Escherichia coli. To gain insight into the functioning of the Dsb system in epsilon-Proteobacteria, where it plays an important role in the colonization process, we studied two homologs of the main Escherichia coli Dsb oxidase (EcDsbA) that are present in the cells of the enteric pathogen Campylobacter jejuni, the most frequently reported bacterial cause of human enteritis in the world.
  
  
  RESULTS
  Phylogenetic analysis suggests the horizontal transfer of the epsilon-Proteobacterial DsbAs from a common ancestor to gamma-Proteobacteria, which then gave rise to the DsbL lineage. Phenotype and enzymatic assays suggest that the two C. jejuni DsbAs play different roles in bacterial cells and have divergent substrate spectra. CjDsbA1 is essential for the motility and autoagglutination phenotypes, while CjDsbA2 has no impact on those processes. CjDsbA1 plays a critical role in the oxidative folding that ensures the activity of alkaline phosphatase CjPhoX, whereas CjDsbA2 is crucial for the activity of arylsulfotransferase CjAstA, encoded within the dsbA2-dsbB-astA operon.
  
  
  CONCLUSIONS
  Our results show that CjDsbA1 is the primary thiol-oxidoreductase affecting life processes associated with bacterial spread and host colonization, as well as ensuring the oxidative folding of particular protein substrates. In contrast, CjDsbA2 activity does not affect the same processes and so far its oxidative folding activity has been demonstrated for one substrate, arylsulfotransferase CjAstA. The results suggest the cooperation between CjDsbA2 and CjDsbB. In the case of the CjDsbA1, this cooperation is not exclusive and there is probably another protein to be identified in C. jejuni cells that acts to re-oxidize CjDsbA1. Altogether the data presented here constitute the considerable insight to the Epsilonproteobacterial Dsb systems, which have been poorly understood so far.
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
authors.forename: Anna D
authors.initials: AD
authors.lastname: Grabowska
authors.affiliation: Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Wywiał
authors.affiliation: Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, Warsaw, Poland.
authors.forename: Stanislaw
authors.initials: S
authors.lastname: Dunin-Horkawicz
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Łasica
authors.affiliation: Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, the Netherlands; World Health Organization Collaborating Centre for Reference and Research on Campylobacter/ World Organisation for Animal Health Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands.
authors.forename: Marc M S M
authors.initials: MM
authors.lastname: Wösten
authors.affiliation: Institute of Science and Technology, Klosterneuburg, Austria.
authors.forename: Anna
authors.initials: A
authors.lastname: Nagy-Staroń
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
authors.forename: Renata
authors.initials: R
authors.lastname: Godlewska
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Bocian-Ostrzycka
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Pieńkowska
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Łaniewski
authors.affiliation: Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, Warsaw, Poland; Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland.
authors.forename: Janusz M
authors.initials: JM
authors.lastname: Bujnicki
authors.affiliation: Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, the Netherlands; World Health Organization Collaborating Centre for Reference and Research on Campylobacter/ World Organisation for Animal Health Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands.
authors.forename: Jos P M
authors.initials: JP
authors.lastname: van Putten
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, University of Warsaw, Warsaw, Poland.
authors.forename: E Katarzyna
authors.initials: EK
authors.lastname: Jagusztyn-Krynicka
mesh_terms: D000371:Agglutination; D000469:Alkaline Phosphatase / Q000378:metabolism; D015239:Arylsulfotransferase / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D016123:Campylobacter jejuni / Q000201:enzymology; D019295:Computational Biology / Q000379:methods*; D004926:Escherichia coli / Q000378:metabolism; D005816:Genetic Complementation Test; D006801:Humans; D007328:Insulin / Q000378:metabolism; D008958:Models, Molecular; D009068:Movement; D009154:Mutation / Q000235:genetics; D010084:Oxidation-Reduction; D010802:Phylogeny; D066329:Protein Aggregates; D011485:Protein Binding; D011490:Protein Disulfide Reductase (Glutathione) / Q000737:chemistry / Q000378:metabolism*; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D007328:Insulin; D066329:Protein Aggregates; D011490:Protein Disulfide Reductase (Glutathione); D015239:Arylsulfotransferase; D000469:Alkaline Phosphatase