A simple laser vaporization source for thermally fragile molecules coupled to a supersonic expansion: application to the spectroscopy of tryptophan

Piuzzi, F.; Dimicoli, I.; Mons, Michel; Tardivel, B.; Zhao, Qingchun

doi:10.1016/s0009-2614(00)00242-6

Cited by 112 publications

(121 citation statements)

References 18 publications

Supporting

Mentioning

118

Contrasting

Unclassified

Order By: Relevance

“…Hence, a final comparison between the experimental and theoretical values of the quadrupole coupling constants (Tables III and IV, respectively) serves to discriminate between these conformers and allows the unequivocal identification of the observed rotamer as conformer IIc+1. This conformer has never been reported in any previous studies of Trp, 3,[22][23][24][25] although IIc+2 conformer -structurally very similar to IIc+1 -has been proposed. 23,28 It seems that the spectral signatures of conformer IIc+1 has been misleadingly attributed to the existence of the conformer IIc+2, based on the relative energies 23 and conformational interconversion processes.…”

Section: Resultssupporting

confidence: 43%

See 1 more Smart Citation

Rotational spectrum of tryptophan

Sanz

Cabezas

Mata

et al. 2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

The rotational spectrum of the natural amino acid tryptophan has been observed for the first time using a combination of laser ablation, molecular beams, and Fourier transform microwave spectroscopy. Independent analysis of the rotational spectra of individual conformers has conducted to a definitive identification of two different conformers of tryptophan, with one of the observed conformers never reported before. The analysis of the 14 N nuclear quadrupole coupling constants is of particular significance since it allows discrimination between structures, thus providing structural information on the orientation of the amino group. Both observed conformers are stabilized by an O-H · · · N hydrogen bond in the side chain and a N-H · · · π interaction forming a chain that reinforce the strength of hydrogen bonds through cooperative effects.

show abstract

Section: Resultssupporting

confidence: 43%

“…Piuzzi et al observed three of those conformers and confirm that they were distinct, using REMPI and holeburning spectroscopies. 22 Simons and co-workers characterized six species through UV hole-burning and infrared iondip spectroscopy and were able to match five of them to SCHEME 1. Schematic representation of Trp.…”

Section: Introductionmentioning

confidence: 99%

Rotational spectrum of tryptophan

Sanz

Cabezas

Mata

et al. 2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…16 However, the understanding of the measurements is often hampered by spectral congestion resulting from the coexistence of multiple conformers and by spectral shifts due to solvent effects in liquid phase or intermolecular interactions in crystals. 19 Modern methods for preparing molecules in the gas phase such as laser desorption followed by fast cooling in a supersonic expansion, 20,21 allow the use of sophisticated UV and IR/UV double resonance laser spectroscopic techniques. 22,23 In general the better resolution and the conformer-selective experiments achieved in gas phase spectroscopic techniques provide more precise information than condensed phase studies.…”

Section: Introductionmentioning

confidence: 99%

Secondary structures of short peptide chains in the gas phase: Double resonance spectroscopy of protected dipeptides

Chin

Dognon

Canuel

et al. 2005

The Journal of Chemical Physics

Self Cite

162

View full text Add to dashboard Cite

The conformational structure of short peptide chains in the gas phase is studied by laser spectroscopy of a series of protected dipeptides, Ac-Xxx-Phe-NH 2 , XxxϭGly, Ala, and Val. The combination of laser desorption with supersonic expansion enables us to vaporize the peptide molecules and cool them internally; IR/UV double resonance spectroscopy in comparison to density functional theory calculations on Ac-Gly-Phe-NH 2 permits us to identify and characterize the conformers populated in the supersonic expansion. Two main conformations, corresponding to secondary structures of proteins, are found to compete in the present experiments. One is composed of a doubly ␥-fold corresponding to the 2 7 ribbon structure. Topologically, this motif is very close to a ␤-strand backbone conformation. The second conformation observed is the ␤-turn, responsible for the chain reversal in proteins. It is characterized by a relatively weak hydrogen bond linking remote NH and CO groups of the molecule and leading to a ten-membered ring. The present gas phase experiment illustrates the intrinsic folding properties of the peptide chain and the robustness of the ␤-turn structure, even in the absence of a solvent. The ␤-turn population is found to vary significantly with the residues within the sequence; the Ac-Val-Phe-NH 2 peptide, with its two bulky side chains, exhibits the largest ␤-turn population. This suggests that the intrinsic stabilities of the 2 7 ribbon and the ␤-turn are very similar and that weakly polar interactions occurring between side chains can be a decisive factor capable of controlling the secondary structure.

show abstract

“…A short, pulsed laser, irradiation allows a very fast evaporation before the thermal degradation of molecules of interest. Furthermore, since most of laser energy is absorbed by graphite matrix rather than biomolecules, the photochemical degradation of molecules can be minimized (Piuzzi et al, 2000). To do this, a mixed graphite-molecule pellet is rotated at the tip of the nozzle of a pulsed valve.…”

Section: Laser Desorptionmentioning

confidence: 99%