Hydrated complexes of tryptophan: ion dip infrared spectroscopy in the ‘molecular fingerprint’ region, 100–2000 cm−1

The infrared spectra of hydrated complexes of tryptophan have been recorded in the gas phase over the range 160–800 cm−1 using double resonance IR-UV ion dip spectroscopy. Despite the problems arising from severe UV spectral overlap of unresolved resonances, the IR measurements, combined with new DFT and ab initio calculations have allowed a re-assessment of the spectral assignments proposed in an earlier combined near-infrared/quantum computational investigation [L. C. Snoek, R. T. Kroemer and J. P. Simons, Phys. Chem. Chem. Phys. 2002, 4, 2130]. It has reinforced the conclusion that hydration leads to conformational restructuring and also served to focus attention on the information that can be provided by spectroscopic measurements obtained in the mid and far IR.

[1]  G. Helden,et al.  Resonant Ionization Using IR Light: A New Tool To Study the Spectroscopy and Dynamics of Gas-Phase Molecules and Clusters , 2003 .

[2]  J. Bakker,et al.  Fingerprint IR spectroscopy to probe amino acid conformations in the gas phase. , 2003, Physical review letters.

[3]  T. Ebata,et al.  C–H stretching vibrations of benzene and toluene in their S1 states observed by double resonance vibrational spectroscopy in supersonic jets , 2002 .

[4]  Kang Taek Lee,et al.  Resonant two-photon ionization study of jet-cooled amino acid: L-phenylalanine and its monohydrated complex , 2002 .

[5]  David F. Plusquellic,et al.  Continuous-wave terahertz spectroscopy of biotin: vibrational anharmonicity in the far-infrared , 2004 .

[6]  D. Levy,et al.  ELECTRONIC-SPECTRUM OF THE AMINO-ACID TRYPTOPHAN COOLED IN A SUPERSONIC MOLECULAR-BEAM , 1985 .

[7]  P. Hobza,et al.  The mid-IR absorption spectrum of gas-phase clusters of the nucleobases guanine and cytosine , 2004 .

[8]  T. Zwier,et al.  The role of water bridges in directing the conformational preferences of 3-indole-propionic acid and tryptamine. , 2001, Journal of the American Chemical Society.

[9]  G. Helden,et al.  Infrared spectroscopy of jet-cooled neutral and ionized aniline-Ar , 1999 .

[10]  T. Zwier,et al.  Direct Measurement of Energy Thresholds to Conformational Isomerization in Tryptamine , 2004, Science.

[11]  A.F.G. van der Meer,et al.  The Free-Electron-Laser user facility FELIX , 1995 .

[12]  M. Jarrold,et al.  Peptides and proteins in the vapor phase. , 2000, Annual review of physical chemistry.

[13]  J. Simons,et al.  Conformational landscapes of aromatic amino acids in the gas phase : infrared and ultraviolet ion dip spectroscopy of tryptophan , 2001 .

[14]  J. Simons,et al.  A spectroscopic and computational exploration of tryptophan–water cluster structures in the gas phase , 2002 .

[15]  Petros Koumoutsakos,et al.  Dispersion corrections to density functionals for water aromatic interactions. , 2004, The Journal of chemical physics.

[16]  J. Simons,et al.  Conformational Structures of 3-Phenyl-1-propionic Acid, Its p-Hydroxy Derivative, and Its Hydrated Clusters , 1997 .

[17]  J. Simons,et al.  Getting into shape: Conformational and supramolecular landscapes in small biomolecules and their hydrated clusters , 2001 .

[18]  K. Kleinermanns,et al.  Molecular physics of building blocks of life under isolated or defined conditions , 2002 .

[19]  J. Simons,et al.  Probing the glycosidic linkage: UV and IR ion-dip spectroscopy of a lactoside. , 2004, Journal of the American Chemical Society.

[20]  T. Zwier.  Laser Spectroscopy of Jet-Cooled Biomolecules and Their Water-Containing Clusters: Water Bridges and Molecular Conformation , 2001 .

[21]  Guido Maes,et al.  Neutral and zwitterionic glycine.H(2)O complexes: A theoretical and matrix-isolation Fourier transform infrared study. , 2004, The Journal of chemical physics.