TY - JOUR
T1 - Hydration profiles of aromatic amino acids
T2 - Conformations and vibrations of l-phenylalanine-(H2O)n clusters
AU - Ebata, Takayuki
AU - Hashimoto, Takayo
AU - Ito, Takafumi
AU - Inokuchi, Yoshiya
AU - Altunsu, Fuat
AU - Brutschy, Bernhard
AU - Tarakeshwar, P.
PY - 2006
Y1 - 2006
N2 - IR-UV double resonance spectroscopy and ab initio calculations were employed to investigate the structures and vibrations of the aromatic amino acid, l-phenylalanine-(H2O)n clusters formed in a supersonic free jet. Our results indicate that up to three water molecules are preferentially bound to both the carbonyl oxygen and the carboxyl hydrogen of l-phenylalanine (l-Phe) in a bridged hydrogen-bonded conformation. As the number of water molecules is increased, the bridge becomes longer. Two isomers are found for l-Phe-(H2O)1, and both of them form a cyclic hydrogen-bond between the carboxyl group and the water molecule. In l-Phe-(H2O)2, only one isomer was identified, in which two water molecules form extended cyclic hydrogen bonds with the carboxyl group. In the calculated structure of l-Phe-(H2O)3 the bridge of water molecules becomes larger and exhibits an extended hydrogen-bond to the π-system. Finally, in isolated l-Phe, the D conformer was found to be the most stable conformer by the experiment and by the ab initio calculation.
AB - IR-UV double resonance spectroscopy and ab initio calculations were employed to investigate the structures and vibrations of the aromatic amino acid, l-phenylalanine-(H2O)n clusters formed in a supersonic free jet. Our results indicate that up to three water molecules are preferentially bound to both the carbonyl oxygen and the carboxyl hydrogen of l-phenylalanine (l-Phe) in a bridged hydrogen-bonded conformation. As the number of water molecules is increased, the bridge becomes longer. Two isomers are found for l-Phe-(H2O)1, and both of them form a cyclic hydrogen-bond between the carboxyl group and the water molecule. In l-Phe-(H2O)2, only one isomer was identified, in which two water molecules form extended cyclic hydrogen bonds with the carboxyl group. In the calculated structure of l-Phe-(H2O)3 the bridge of water molecules becomes larger and exhibits an extended hydrogen-bond to the π-system. Finally, in isolated l-Phe, the D conformer was found to be the most stable conformer by the experiment and by the ab initio calculation.
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U2 - 10.1039/b609229b
DO - 10.1039/b609229b
M3 - Article
C2 - 17043722
AN - SCOPUS:34247183808
SN - 1463-9076
SP - 4783
EP - 4791
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
ER -