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Proc Natl Acad Sci U S A. 2018 Jul 17;115(29):7587-7592. doi: 10.1073/pnas.1808351115. Epub 2018 Jul 2.

An aryl-homoserine lactone quorum-sensing signal produced by a dimorphic prosthecate bacterium.

Author information

1
Integrative Microbiology Research Centre, South China Agricultural University, 510642 Guangzhou, People's Republic of China.
2
Department of Microbiology, University of Washington, Seattle, WA 98195.
3
Division of Biological Sciences, University of Missouri, Columbia, MO 65211.
4
Integrative Microbiology Research Centre, South China Agricultural University, 510642 Guangzhou, People's Republic of China; epgreen@uw.edu.

Abstract

Many species of Proteobacteria produce acyl-homoserine lactone (AHL) compounds as quorum-sensing (QS) signals for cell density-dependent 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.

KEYWORDS:

Prosthecomicrobium; bacterial communication; phenylacetate; sociomicrobiology; α-Proteobacteria

PMID:
29967162
PMCID:
PMC6055194
[Available on 2019-01-17]
DOI:
10.1073/pnas.1808351115
[Indexed for MEDLINE]

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