title: Infrared study of the bacterial autoinducer N-hexanoyl-homoserine lactone (C6-HSL) in the gas-phase, water, and octanol solutions.
abstract: The N-hexanoyl-homoserine lactone (C6-HSL) molecule has been investigated by means of infrared multiphoton dissociation (IRMPD) and Fourier-transform infrared spectroscopy (FT-IR) under different conditions in an attempt to mimic biological situations encountered in communication between bacteria for quorum sensing. The protonated molecular ion was studied in the gas-phase that corresponds to a solvent-free situation somewhat analogous to that encountered in the receptor. The simulation of the IRMPD spectrum of the isolated ion was then conducted by means of quantum chemistry calculations in vacuum. In the case of the neutral species, the FT-IR spectra were recorded in D(2)O, mimicking the cytosolic and extracellular media as well as in 1-octanol that is often used for simulation of cell membranes. The interpretation was conducted by considering a C6-HSL molecule in its endo or exo conformation hydrogen-bonded to, respectively, six D(2)O and four 1-octanol molecules. A satisfying agreement with the experimental FT-IR studies conducted in solution at room temperature was obtained as long as a continuum IEFPCM model was added to the explicit solvent environment.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-747, Korea.
authors.forename: Jiah
authors.initials: J
authors.lastname: Kim
authors.forename: Seong Keun
authors.initials: SK
authors.lastname: Kim
authors.forename: Gilles
authors.initials: G
authors.lastname: Grégoire
authors.forename: Bruno
authors.initials: B
authors.lastname: Manil
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Schermann
mesh_terms: D020003:1-Octanol / Q000737:chemistry; D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D003903:Deuterium; D005740:Gases / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D018716:Molecular Mimicry; D053038:Quorum Sensing; D012097:Repressor Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014867:Water
chemical_list: D001426:Bacterial Proteins; D005740:Gases; C085427:LuxI protein, Bacteria; C104908:N-hexanoyl-L-homoserine lactone; D012097:Repressor Proteins; D012996:Solutions; D012997:Solvents; D015534:Trans-Activators; D014157:Transcription Factors; D014867:Water; C064778:LuxR autoinducer binding proteins; D003903:Deuterium; D020003:1-Octanol; D015107:4-Butyrolactone