N-Acylhomoserine lactone quorum-sensing molecules are modified and degraded by Rhodococcus erythropolis W2 by both amidolytic and novel oxidoreductase activities.
The Rhodococcus erythropolis strain W2 has been shown previously to degrade the N-acylhomoserine lactone (AHL) quorum-sensing signal molecule N-hexanoyl-L-homoserine lactone, produced by other bacteria. Data presented here indicate that this Gram-positive bacterium is also capable of using various AHLs as the sole carbon and energy source. The enzymic activities responsible for AHL inactivation were investigated in R. erythropolis cell extracts and in whole cells. R. erythropolis cells rapidly degraded AHLs with 3-oxo substituents but exhibited relatively poor activity against the corresponding unsubstituted AHLs. Investigation of the mechanism(s) by which R. erythropolis cells degraded AHLs revealed that 3-oxo compounds with N-acyl side chains ranging from C8 to C14 were initially converted to their corresponding 3-hydroxy derivatives. This oxidoreductase activity was not specific to 3-oxo-AHLs but also allowed the reduction of compounds such as N-(3-oxo-6-phenylhexanoyl)homoserine lactone (which contains an aromatic acyl chain substituent) and 3-oxododecanamide (which lacks the homoserine lactone ring). It also reduced both the D- and L-isomers of n-(3-oxododecanoyl)-L-homoserine lactone. A second AHL-degrading activity was observed when R. erythropolis cell extracts were incubated with N-(3-oxodecanoyl)-L-homoserine lactone (3O,C10-HSL). This activity was both temperature- and pH-dependent and was characterized as an amidolytic activity by HPLC analysis of the reaction mixture treated with dansyl chloride. This revealed the accumulation of dansylated homoserine lactone, indicating that the 3O,C10-HSL amide had been cleaved to yield homoserine lactone. R. erythropolis is therefore capable of modifying and degrading AHL signal molecules through both oxidoreductase and amidolytic activities.
Uroz
Stéphane
S
Interactions Plantes et Micro-organismes de la Rhizosphère, Institut des Sciences du Végétal, CNRS, Bâtiment 23, Avenue de la Terrasse, 91198 Gif-sur-Yvette CEDEX, France.
Chhabra
Siri Ram
SR
Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Cámara
Miguel
M
Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Williams
Paul
P
Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Oger
Phil
P
Laboratoire des Sciences de la Terre, École Normale Supérieure de Lyon, 43 Allée D'Italie, 69364 Lyon CEDEX 07, France.
Dessaux
Yves
Y
Interactions Plantes et Micro-organismes de la Rhizosphère, Institut des Sciences du Végétal, CNRS, Bâtiment 23, Avenue de la Terrasse, 91198 Gif-sur-Yvette CEDEX, France.
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D000581:Amidohydrolases / Q000378:metabolism*; D003619:Dansyl Compounds / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D010088:Oxidoreductases / Q000378:metabolism*; D012240:Rhodococcus / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature
D003619:Dansyl Compounds; C109860:N-(3-oxododecanoyl)homoserine lactone; C088386:homoserine lactone; D006714:Homoserine; D010088:Oxidoreductases; D000581:Amidohydrolases; D015107:4-Butyrolactone; C029038:dansyl chloride