title: Aii20J, a wide-spectrum thermostable N-acylhomoserine lactonase from the marine bacterium Tenacibaculum sp. 20J, can quench AHL-mediated acid resistance in Escherichia coli.
abstract: Acyl homoserine lactones (AHLs) are produced by many Gram-negative bacteria to coordinate gene expression in cellular density dependent mechanisms known as quorum sensing (QS). Since the disruption of the communication systems significantly reduces virulence, the inhibition of quorumsensing processes or quorum quenching (QQ) represents an interesting anti-pathogenic strategy to control bacterial infections. Escherichia coli does not produce AHLs but possesses an orphan AHL receptor, SdiA, which is thought to be able to sense the QS signals produced by other bacteria and controls important traits as the expression of glutamate-dependent acid resistance mechanism, therefore constituting a putative target for QQ. A novel AHL-lactonase, named Aii20J, has been identified, cloned and over expressed from the marine bacterium Tenacibaculum sp. strain 20 J presenting a wide-spectrum QQ activity. The enzyme, belonging to the metallo-β-lactamase family, shares less than 31 % identity with the lactonase AiiA from Bacillus spp. Aii20J presents a much higher specific activity than the Bacillus enzyme, maintains its activity after incubation at 100 ºC for 10 minutes, is resistant to protease K and α-chymotrypsin, and is unaffected by wide ranges of pH. The addition of Aii20J (20 μg/mL) to cultures of E. coli K-12 to which OC6-HSL was added resulted in a significant reduction in cell viability in comparison with the acidresistant cultures derived from the presence of the signal. Results confirm the interaction between AHLs and SdiA in E. coli for the expression of virulence-related genes and reveal the potential use of Aii20J as anti-virulence strategy against important bacterial pathogens and in other biotechnological applications.
authors.affiliation: Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Mayer
authors.affiliation: Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.|School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: M
authors.initials: M
authors.lastname: Romero
authors.affiliation: Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Muras
authors.affiliation: Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain. anamaria.otero@usc.es.
authors.forename: A
authors.initials: A
authors.lastname: Otero
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology / Q000235:genetics; D002265:Carboxylic Ester Hydrolases / Q000235:genetics* / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability; D053038:Quorum Sensing; D060493:Tenacibaculum / Q000201:enzymology* / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014774:Virulence / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D054742:Acyl-Butyrolactones; D029968:Escherichia coli Proteins; D015534:Trans-Activators; C490806:sdiA protein, E coli; D002265:Carboxylic Ester Hydrolases; C432003:N-acyl homoserine lactonase; D002918:Chymotrypsin; C117608:alpha-chymotrypsin; D001618:beta-Lactamases
keywords: E. coli; Lactonase; Quorum sensing; Quorum-quenching acylhomoserine lactones; SdiA