Abstract

The identification of two unsaturated N-acylhomoserine lactones (AHLs) produced by Rhodobacter sphaeroides bacteria, based on liquid chromatography (LC) coupled to a hybrid quadrupole linear ion trap (LTQ)-Fourier transform ion cyclotron resonance (FTICR) mass spectrometer upon electrospray ionization (ESI), is presented. Along the confirmation of the signaling molecule already described in the literature, i.e. (Z)-N-tetradec-7-enoyl-homoserine lactone (C14:1-HSL), we have discovered the occurrence, at low yet significant levels, of another monounsaturated compound, C12:1-HSL, which may extend the number of small diffusible chemical signals known for R. sphaeroides. Both unsaturated AHLs were identified by high resolution FTICR mass spectrometry in extracts of bacterial culture media and the occurrence of a C=C bond was assessed upon their conversion to bromohydrins. Collision induced dissociation (CID) spectra were then collected on the LTQ mass analyser. A careful comparison of tandem MS spectra of monounsaturated (i.e., C12:1-HSL and C14:1-HSL) and saturated AHLs (i.e. C12-HSL and C14-HSL) led to emphasise two series of product ions, exhibiting 14 Da-spaced m/z ratios. Both series were referred to progressive fragmentations at the aliphatic end of the AHL acyl chains, followed by neutral losses of terminal alkenes (i.e., CH2=CH(CH2)nH). In particular, the series located at the higher end of the explored m/z range (> 200 Da), observed only for monounsaturated species, enabled the location of the C=C bond between carbons 7 and 8 of the acyl chain.

Autore Pugliese

• Losito Ilario , Cataldi Tommaso

Tutti gli autori

• LOSITO I.;CATALDI T.

Titolo volume/Rivista

Non Disponibile

Anno di pubblicazione

2011

ISSN

0951-4198

ISBN

Non Disponibile

Numero di citazioni Wos

7

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

8

Ultimo Aggiornamento Citazioni

Non Disponibile

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile