1. An aryl-homoserine lactone quorum-sensing signal produced by a dimorphic prosthecate bacterium.
- Author
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Lisheng Liao, Schaefer, Amy L., Coutinho, Bruna G., Brown, Pamela J. B., and Greenberg, E. Peter
- Subjects
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PROTEOBACTERIA , *QUORUM sensing , *GENETIC regulation , *SYNTHASES , *LACTONES , *FATTY acids , *CARRIER proteins - Abstract
Many species of Proteobacteria produce acyl-homoserine lactone (AHL) compounds as quorum-sensing (QS) signals for cell densitydependent gene regulation. Most known AHL synthases, LuxI-type enzymes, produce fatty AHLs, and the fatty acid moiety is derived from an acyl-acyl carrier protein (ACP) intermediate in fatty acid biosynthesis. Recently, a class of LuxI homologs has been shown to use CoA-linked aromatic or amino acid substrates for AHL synthesis. By using an informatics approach, we found the CoA class of LuxI homologs exists primarily in α-Proteobacteria. The genome of Prosthecomicrobium hirschii, a dimorphic prosthecate bacterium, possesses a luxI-like AHL synthase gene that we predicted to encode a CoA-utilizing enzyme. We show the P. hirschii LuxI homolog catalyzes synthesis of phenylacetyl-homoserine lactone (PA-HSL). Our experiments show P. hirschii obtains phenylacetate from its environment and uses a CoA ligase to produce the phenylacetyl-CoA substrate for the LuxI homolog. By using an AHL degrading enzyme, we showed that PA-HSL controls aggregation, biofilm formation, and pigment production in P. hirschii. These findings advance a limited understanding of the CoA-dependent AHL synthases. We describe how to identify putative members of the class, we describe a signal synthesized by using an environmental aromatic acid, and we identify phenotypes controlled by the aryl-HSL. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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