Rotational spectrum of tryptophan
M Eugenia Sanz1, Carlos Cabezas1, Santiago Mata1
1Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Unidad Asociada CSIC, Parque Científico Uva, Universidad de Valladolid, 47011 Valladolid, Spain.
The Journal of Chemical Physics
|June 2, 2014
Summary
The first rotational spectrum of the amino acid tryptophan was observed, revealing two distinct conformers. One conformer is novel, and analysis provided structural insights into the amino group orientation.
Area of Science:
- Molecular Spectroscopy
- Quantum Chemistry
- Biophysical Chemistry
Background:
- Tryptophan is a crucial natural amino acid with diverse biological roles.
- Understanding tryptophan's conformational landscape is key to elucidating its function.
- Previous studies lacked detailed structural information on tryptophan conformers.
Purpose of the Study:
- To observe and analyze the rotational spectrum of tryptophan for the first time.
- To identify and characterize different conformers of tryptophan.
- To gain structural insights into the amino group orientation and stabilizing interactions.
Main Methods:
- Laser ablation coupled with molecular beams.
- Fourier transform microwave spectroscopy.
- Analysis of rotational spectra and (14)N nuclear quadrupole coupling constants.
Main Results:
- The rotational spectrum of tryptophan was successfully observed.
- Two distinct conformers of tryptophan were identified.
- One of the identified conformers is reported for the first time.
- Structural information on amino group orientation was obtained via nuclear quadrupole coupling.
Conclusions:
- The study provides the first experimental evidence of tryptophan conformers using rotational spectroscopy.
- Identified conformers are stabilized by specific hydrogen bonding and pi-interactions.
- Cooperative effects between hydrogen bonds enhance structural stability.
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