title: Biochemical and functional characterization of a periplasmic disulfide oxidoreductase from Neisseria meningitidis essential for meningococcal viability.
abstract: TlpAs (thioredoxin-like proteins) are bacterial thioredoxin-like periplasmic disulfide oxidoreductases generally involved in cytochrome c maturation (Ccm) process. They contain a characteristic CXXC active site motif involved in disulfide exchange reaction. In the human pathogenic Neisseria meningitidis species, no TlpA has been characterized so far. In the present study, using an in silico analysis, we identified a putative periplasmic TlpA, called TlpA2. Biochemical and kinetic characterizations of the soluble form of TlpA2, tTlpA2 (truncated TlpA2), were performed. A reduction potential of -0.230 V at pH 7 was calculated, suggesting that TlpA2 acts as a reductant in the oxidative environment of the periplasm. Using a second-order reactive probe, high pKapp (apparent pKa) values were determined for the two cysteines of the SCXXC motif. The tTlpA2 was shown to be efficiently reduced by the N-terminal domain of the DsbD, whereas tTlpA2 reduced a mimetic peptide of cytochrome c' with a catalytic efficiency similar to that observed with other disulfide oxidoreductase like ResA. Moreover, the corresponding gene tlpA2 was shown to be essential for the pathogen viability and able to partially complement a Bordetella pertussis CcsX mutant. Together, these data support an essential role of TlpA2 in the Ccm process in N. meningitidis.
authors.affiliation: *IMoPA, Équipe Enzymologie Moléculaire et Structurale, UMR 7365 CNRS-Université de Lorraine, Bâtiment Biopôle, Faculté de Médecine, 9 avenue de la Foreât de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France.
authors.forename: Adeline
authors.initials: A
authors.lastname: Gand
authors.affiliation: *IMoPA, Équipe Enzymologie Moléculaire et Structurale, UMR 7365 CNRS-Université de Lorraine, Bâtiment Biopôle, Faculté de Médecine, 9 avenue de la Foreât de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Selme-Roussel
authors.affiliation: *IMoPA, Équipe Enzymologie Moléculaire et Structurale, UMR 7365 CNRS-Université de Lorraine, Bâtiment Biopôle, Faculté de Médecine, 9 avenue de la Foreât de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Collin
authors.affiliation: *IMoPA, Équipe Enzymologie Moléculaire et Structurale, UMR 7365 CNRS-Université de Lorraine, Bâtiment Biopôle, Faculté de Médecine, 9 avenue de la Foreât de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Branlant
authors.affiliation: *IMoPA, Équipe Enzymologie Moléculaire et Structurale, UMR 7365 CNRS-Université de Lorraine, Bâtiment Biopôle, Faculté de Médecine, 9 avenue de la Foreât de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Jacob
authors.affiliation: *IMoPA, Équipe Enzymologie Moléculaire et Structurale, UMR 7365 CNRS-Université de Lorraine, Bâtiment Biopôle, Faculté de Médecine, 9 avenue de la Foreât de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Boschi-Muller
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D004220:Disulfides / Q000378:metabolism*; D006801:Humans; D008589:Meningococcal Infections / Q000378:metabolism / Q000382:microbiology / Q000473:pathology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000201:enzymology*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D019897:Periplasm / Q000201:enzymology*; D033903:Periplasmic Proteins / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013879:Thioredoxins / Q000378:metabolism*
chemical_list: D004220:Disulfides; D033903:Periplasmic Proteins; D013879:Thioredoxins; D010088:Oxidoreductases; C077913:periplasmic protein disulfide oxidoreductase