title: Quorum quenching activity in Anabaena sp. PCC 7120: identification of AiiC, a novel AHL-acylase.
abstract: Many bacteria use quorum sensing (QS) to coordinate responses to environmental changes. In Gram-negative bacteria, the most extensively studied QS systems rely on the use of N-acylhomoserine lactones (AHLs) signal molecules. Some bacteria produce enzymes that are able to inactivate AHL signals produced by other bacteria and hence interfere with QS-mediated processes via a phenomenon known as quorum quenching. Acylase-type AHL degradation activity has been found in the biomass of the filamentous nitrogen-fixing cyanobacterium Anabaena (Nostoc) sp. PCC 7120, being absent from the culture media. The gene all3924 has been identified and cloned whose product exhibits homology to the acylase QuiP of Pseudomonas aeruginosa PAO1, demonstrating that it is at least partially responsible for the AHL-acylase activity. The recombinant enzyme, which was named auto-inducer inhibitor from Cyanobacteria (AiiC), shows broad acyl-chain length specificity. Because the presence of AHLs in the biomass of nitrogen-fixing cultures of Anabaena sp. PCC 7120 has been described recently, AiiC could represent a self-modulatory system to control the response to its own QS signals but could also be involved in the interference of signalling within complex microbial communities in which Cyanobacteria are present.
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, Santiago, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Romero
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Diggle
authors.forename: Stephan
authors.initials: S
authors.lastname: Heeb
authors.forename: Miguel
authors.initials: M
authors.lastname: Cámara
authors.forename: Ana
authors.initials: A
authors.lastname: Otero
mesh_terms: D054742:Acyl-Butyrolactones / Q000737:chemistry / Q000378:metabolism*; D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism*; D000606:Amino Sugars / Q000737:chemistry / Q000378:metabolism*; D017033:Anabaena / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000145:classification; D015964:Gene Expression Regulation, Bacterial; D007783:Lactones / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism; D053038:Quorum Sensing
chemical_list: D054742:Acyl-Butyrolactones; D000606:Amino Sugars; D001426:Bacterial Proteins; D007783:Lactones; C042419:N-acylkansosamine; D000581:Amidohydrolases; C019665:amidase