title: GqqA, a novel protein in Komagataeibacter europaeus involved in bacterial quorum quenching and cellulose formation.
abstract: BACKGROUND
  We report on the functional screening and identification of an active quorum quenching (QQ) gene in the Komagataeibacter europaeus strain CECT 8546, which is a member of the acetic acid bacteria (AAB).
  
  
  RESULTS
  Using a previously published screening protocol (Schipper et al., in Appl Environ Microbiol 75:224-233, 2009. doi: 10.1128/AEM.01389-08 ) for QQ genes, we identified a single gene, designated gqqA, that interfered strongly with bacterial quorum sensing (QS) in various reporter strains. It encodes for a 281-amino acid protein with a molecular mass of 30 kDa. Although the GqqA protein is similar to predicted prephenate dehydratases, it does not complement Escherichia coli mutants of the pheA gene, thus indicating a potentially different function. Recombinant GqqA protein attenuated QS-dependent pyocyanin production and swarming motility in the Pseudomonas aeruginosa strain PAO1. Moreover, GqqA quenched the QS response of the Agrobacterium tumefaciens NTL4 and the Chromobacterium violaceum CV026 reporter strains. Interestingly, the addition of recombinant GqqA protein to growing cultures of the Komagataeibacter europaeus strain CECT 8546 altered the cellulose production phenotype of CECT 8546 and other AAB strains. In the presence of GqqA protein, cells were planktonic, and no visible cellulose biofilms formed. The addition of low levels of N-acylhomoserine lactones maintained the biofilm formation phenotype.
  
  
  CONCLUSIONS
  Our data provide evidence for an interconnection between QS and AAB cellulose biofilm formation as well as QQ activity of the GqqA protein.
authors.affiliation: Biotecnología Enológica. Dept. Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, C/Marcel.lí Domingo s/n., 43007, Tarragona, Spain.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Valera
authors.affiliation: Biotecnología Enológica. Dept. Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, C/Marcel.lí Domingo s/n., 43007, Tarragona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Mas
authors.affiliation: Abteilung für Mikrobiologie und Biotechnologie, Biozentrum Klein Flottbek, Universität Hamburg, Ohnhorststr. 18, 22609, Hamburg, Germany.
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Streit
authors.affiliation: Biotecnología Enológica. Dept. Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, C/Marcel.lí Domingo s/n., 43007, Tarragona, Spain. estibaliz.mateo@ehu.eus.|Departamento de Inmunología, Microbiología y Parasitología, Facultad de Medicina y Odontología, Universidad del País Vasco/Euskal Herriko Unibertsitatea UPV/EHU, Barrio Sarriena s/n., 48940, Leioa, Spain. estibaliz.mateo@ehu.eus.
authors.forename: Estibaliz
authors.initials: E
authors.lastname: Mateo
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D016947:Acetobacteraceae / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism; D053038:Quorum Sensing / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; C088386:homoserine lactone; D002482:Cellulose; D015107:4-Butyrolactone
keywords: Acetic acid bacteria; Genomic fosmid library; Homoserine lactone; Quorum quenching; Vinegar