Identification of new N-acylhomoserine lactone signalling compounds of Dinoroseobacter shibae DFL-12(T) by overexpression of luxI genes.
Bacteria of the Roseobacter clade are widespread in the ocean and occur in many different habitats. In the genome of Dinoroseobacter shibae DFL-12, luxI homologous genes that encode synthases responsible for the formation of N-acylhomoserine lactones (AHLs) have been described. These compounds are known autoinducers that regulate several biological traits-namely, flagella formation and cell differentiation-in D. shibae through quorum sensing. The AHLs produced by D. shibae mainly consisted of N-octadecadienoylhomoserine lactone (C18:2-AHL) and N-octadecenoylhomoserine lactone (C18:1-HSL). In the wild type these AHLs are synthesized only in low abundance. The luxI genes were therefore expressed in Escherichia coli; this resulted in the formation of AHLs mostly different from those found in the D. shibae wild type. A luxI1 -deficient mutant of D. shibae was then reprovided with an overexpressed luxI1 gene. This strain produced large amounts of C18:2-AHL and C18:1-AHL, allowing full characterization of these compounds by mass spectrometric techniques and derivatization. Synthesis of the proposed structures confirmed that the major compound is (2E,11Z)-N-octadeca-2,11-dienoylhomoserine lactone (6, C18:2-HSL), accompanied by (Z)-N-octadec-11-enoylhomoserine lactone (5, C18:1-HSL). AHL 6 has not been reported before from other organisms and contains an unusual 2E double bond.
Technische Universität Braunschweig, Institut für Organische Chemie, Hagenring 30, 38106 Braunschweig (Germany).
Alexander
A
Neumann
Diana
D
Patzelt
Irene
I
Wagner-Döbler
Stefan
S
Schulz
D054742:Acyl-Butyrolactones / Q000737:chemistry / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005798:Genes, Bacterial / Q000235:genetics; D008968:Molecular Conformation; D041902:Rhodobacteraceae / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D054742:Acyl-Butyrolactones; D001426:Bacterial Proteins; C085427:LuxI protein, Bacteria; D014157:Transcription Factors
bacteria; chemical communication; gas chromatography; mass spectrometry; quorum sensing