|
type |
Journal Article |
authors |
Spirig T, Tiaden A, Kiefer P, Buchrieser C, Vorholt JA, Hilbi H. |
title |
The Legionella autoinducer synthase LqsA produces an alpha-hydroxyketone signaling molecule |
journal |
J Biol Chem |
Activity |
cqsa |
Family |
cqsa |
sel |
selected |
ui |
18411263 |
year |
(2008) |
volume |
283 |
number |
26 |
pages |
18113-23 |
| |
abstract |
The opportunistic pathogen Legionella pneumophila replicates in human lung macrophages and in free-living amoebae. To accommodate the transfer between host cells, L. pneumophila switches from a replicative to a transmissive phase. L. pneumophila harbors a gene cluster homologous to the Vibrio cholerae cqsAS quorum sensing system, encoding a putative autoinducer synthase (lqsA) and a sensor kinase (lqsS), which flank a response regulator (lqsR). LqsR is an element of the L. pneumophila virulence regulatory network, which promotes pathogen-host cell interactions and inhibits entry into the replicative growth phase. Here, we show that lqsA functionally complements a V. cholerae cqsA autoinducer synthase deletion mutant and, upon expression in L. pneumophila or Escherichia coli, produces the diffusible signaling molecule LAI-1 (Legionella autoinducer-1). LAI-1 is distinct from CAI-1 (Cholerae autoinducer-1) and was identified as 3-hydroxypentadecan-4-one using liquid chromatography coupled to high resolution tandem mass spectrometry. The activity of both LqsA and CqsA was abolished upon mutation of a conserved lysine, and covalent binding of the cofactor pyridoxal 5'-phosphate to this lysine was confirmed by mass spectrometry. Thus, LqsA and CqsA belong to a family of pyridoxal 5'-phosphate-dependent autoinducer synthases, which produce the alpha-hydroxyketone signaling molecules LAI-1 and CAI-1. |
last changed |
2009/08/25 13:40 |
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