title: Overproduction of the secretin OutD suppresses the secretion defect of an Erwinia chrysanthemi outB mutant.
abstract: OutB is a component of the Erwinia chrysanthemi Out secretion machinery. Homologues of OutB have been described in two other bacteria, Klebsiella oxytoca and Aeromonas hydrophila, but their requirement in the secretion process seems to be different. Study of OutB topology with the BlaM topology probe suggests that it is an inner-membrane protein with a large periplasmic domain. However, fractionation experiments indicate that it could be associated with the outer membrane through its C-terminal part. The secretion deficiency of an Erw. chrysanthemi outB mutant can be reversed by the addition of an inducer of the kdgR regulon. It was shown that this effect results from the increased expression of the secretin OutD and that secretion can be restored in an outB mutant by introducing the outD gene on a plasmid. Several experiments suggest an interaction between OutB and OutD. In Erw. chrysanthemi, the presence of OutD stabilizes OutB. OutD expressed in Escherichia coli can be protected from proteolytic degradation by the coexpression of OutB. This effect does not require the N-terminal, transmembrane segment of outB. OutB can be cross-linked with OutD by formaldehyde. These results indicate that OutB could act with OutD in the functioning of the Out secretion machinery.
authors.affiliation: Unité Microbiologie et Génétique Composante INSA, UMR CNRS-INSA-UCB 5577, INSA Bat 406, 20 Av Einstein, 69621 Villeurbanne, France1.
authors.forename: Guy
authors.initials: G
authors.lastname: Condemine
authors.affiliation: Unité Microbiologie et Génétique Composante INSA, UMR CNRS-INSA-UCB 5577, INSA Bat 406, 20 Av Einstein, 69621 Villeurbanne, France1.
authors.forename: Vladimir E
authors.initials: VE
authors.lastname: Shevchik
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002458:Cell Fractionation; D016974:Dickeya chrysanthemi / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D015964:Gene Expression Regulation, Bacterial; D015151:Immunoblotting; D008025:Ligases; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D011133:Polysaccharide-Lyases / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C106887:OutD protein, Erwinia chrysanthemi; D011133:Polysaccharide-Lyases; C023911:pectate lyase; D008025:Ligases; C080136:OutB protein, Bacillus subtilis